validator/validator-main.protoascii

# DEPRECATED: This value is no longer updated.
min_validator_revision_required: 475

# DEPRECATED: This value is no longer updated.
spec_file_revision: 1188

styles_spec_url: "https://amp.dev/documentation/guides-and-tutorials/develop/style_and_layout/style_pages/"
script_spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/validation-workflow/validation_errors/#custom-javascript-is-not-allowed"

# Validator extensions.
# =====================
# In addition to the rules in this file, the Validator honors the rules
# in the extensions/*/validator-*.protoascii files. This makes it
# easy to organize the rules for extensions next to their Javascript
# implementation.
# Please read how the rules in this file works:
# https://github.com/ampproject/amphtml/blob/fc447110e86db57e4391bf5c50de8dd2bf75e18f/docs/component-validator-rules.md

# Rules for AMP HTML
# https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml

doc: {
  html_format: AMP4EMAIL
  max_bytes: 200000
  max_bytes_spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/email-spec/amp-email-format/?format=email"
}

tags: {
  html_format: AMP
  html_format: AMP4EMAIL
  tag_name: "!DOCTYPE"
  spec_name: "html doctype"
  descriptive_name: "html !doctype"
  mandatory_parent: "$ROOT"
  mandatory: true
  unique: true
  explicit_attrs_only: true
  attrs: {
    name: "html"
    mandatory: true
    value: ""
  }
  # `lang` is not supported per spec but is allowed because it has been observed
  # on existing AMP documents.
  attrs: {
    name: "lang"
    deprecation: "html"
    deprecation_url: "https://github.com/ampproject/amphtml/issues/25926"
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
# AMP4ADS may need time to transition <!doctype> to using explicit attrs only.
# Tracking in b/123227526 to merge into tagspec with spec name "html doctype".
tags: {
  html_format: AMP4ADS
  tag_name: "!DOCTYPE"
  spec_name: "html doctype (AMP4ADS)"
  descriptive_name: "html !doctype"
  mandatory_parent: "$ROOT"
  mandatory: true
  unique: true
  attrs: {
    name: "html"
    mandatory: true
    value: ""
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}

# Below, we list the allowed elements in the order in which they are appear
# in the spec in section 4 "The Elements of HTML"
# (http://www.w3.org/TR/html5/single-page#html-elements).

# 4.1 The root element
# 4.1.1 The html element
tags: {  # HTML tag for non-transformed AMP.
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  disabled_by: "transformed"
  tag_name: "HTML"
  mandatory: true
  mandatory_parent: "!DOCTYPE"
  unique: true
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
tags: {  # HTML tag for transformed AMP.
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "HTML"
  spec_name: "html (transformed)"
  mandatory: true
  mandatory_parent: "!DOCTYPE"
  unique: true
  attrs: {
    name: "i-amphtml-layout"
    value: ""
  }
  attrs: {
    name: "i-amphtml-no-boilerplate"
    value: ""
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}

# 4.2 Document metadata
# 4.2.1 The head element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "HEAD"
  mandatory: true
  mandatory_parent: "HTML"
  unique: true
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
# 4.2.2 The title element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "TITLE"
  spec_name: "title"
  attrs: { name: "[text]" }
}
tags: {
  html_format: AMP4EMAIL
  tag_name: "TITLE"
  spec_name: "title [AMP4EMAIL]"
  attrs: { name: "[text]" }
  deprecation: "Title tags in email have no meaning. This tag may become invalid in the future."
  deprecation_url: "https://github.com/ampproject/amphtml/issues/22318"
}

# 4.2.3 the base element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "BASE"
  unique: true
  mandatory_parent: "HEAD"
  # We only allow "/" right now because other value can cause havoc with PWA
  # implementations. In the future, it may be possible to widen this to any
  # absolute URL.
  attrs: {
    name: "href"
    value: "/"
  }
  attrs: {
    name: "target"
    value_casei: "_blank"
    value_casei: "_self"
    value_casei: "_top"
  }
}
# Disallowed.
# 4.2.4 the link element
attr_lists: {
  name: "common-link-attrs"
  attrs: { name: "charset" value_casei: "utf-8" }
  attrs: { name: "color" }
  attrs: { name: "crossorigin" }
  attrs: {
    name: "fetchpriority"
    value_casei: "high"
    value_casei: "low"
    value_casei: "auto"
  }
  attrs: { name: "hreflang" }
  attrs: { name: "media" }
  attrs: { name: "sizes" }
  attrs: { name: "target" }
  attrs: { name: "type" }
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "LINK"
  spec_name: "link rel="
  disallowed_ancestor: "TEMPLATE"
  attrs: { name: "href" }
  attrs: {
    name: "rel"
    mandatory: true
    # There are a wide variety of link rel attribute values used in the wild as
    # this attribute is used as meta-data for any html client such as search
    # engines. Unfortunately, there are also a number of attribute values which
    # have behavioral impacts in modern browsers. A few places where these are
    # loosely documented include:
    # - http://microformats.org/wiki/existing-rel-values
    # - http://www.iana.org/assignments/link-relations/link-relations.xhtml
    # - https://html.spec.whatwg.org/#linkTypes
    # We denylist a few specific values which have browser behavior that could
    # negatively impact performance.
    # TODO(gregable): This could be improved such that the error message would
    # report which value in a list is the one causing problems.
    disallowed_value_regex: "(^|\\s)("  # Values are space separated.
        "canonical|"  # Handled separately below, has specific requirements.
        "components|"
        "import|"
        "manifest|"  # Handled separately below, has specific requirements.
        "modulepreload|"  # Handled separately below, has specific requirements.
        "preload|"  # Handled separately below, has specific requirements.
        "serviceworker|"
        "stylesheet|"  # Handled separately below, has specific requirements.
        "subresource"
        ")(\\s|$)"
    # It is worth noting that user-authored tags for dns-prefectch, preconnect,
    # prefetch, and prerender will be disabled by the transformations applied
    # in the AMP Cache. Therefore, these hints will only be used on publisher
    # origins, not on the AMP Cache.
  }
  attr_lists: "common-link-attrs"
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
tags: {
  html_format: AMP
  tag_name: "LINK"
  spec_name: "link rel=canonical"
  descriptive_name: "link rel=canonical"
  mandatory_parent: "HEAD"
  mandatory: true
  unique: true
  attrs: {
    name: "href"
    mandatory: true
    value_url: {
      protocol: "http"
      protocol: "https"
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: {
    name: "rel"
    value_casei: "canonical"
    mandatory: true
    dispatch_key: NAME_VALUE_DISPATCH
  }
  attr_lists: "common-link-attrs"
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
# Allow <link rel="manifest" ...> but not <link rel="manifest foo" ...>
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "LINK"
  spec_name: "link rel=manifest"
  descriptive_name: "link rel=manifest"
  mandatory_parent: "HEAD"
  satisfies_condition: "amp-app-banner data source"
  attrs: {
    name: "href"
    mandatory: true
    value_url: {
      protocol: "https"
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: {
    name: "rel"
    value_casei: "manifest"
    mandatory: true
    dispatch_key: NAME_VALUE_DISPATCH
  }
  attr_lists: "common-link-attrs"
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
tags: {
  html_format: AMP
  tag_name: "LINK"
  spec_name: "link rel=modulepreload"
  descriptive_name: "link rel=modulepreload"
  mandatory_parent: "HEAD"
  attrs: {
    name: "as"
    mandatory: true
    value: "script"
  }
  attrs: {
    name: "crossorigin"
    mandatory: true
    value: "anonymous"
  }
  attrs: {
    name: "href"
    mandatory: true
    value_regex: ".*\\.mjs$"
  }
  attrs: {
    name: "rel"
    mandatory: true
    value_casei: "modulepreload"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "LINK"
  spec_name: "link rel=preload"
  descriptive_name: "link rel=preload"
  disallowed_ancestor: "TEMPLATE"
  attrs: { name: "as" }
  attrs: { name: "href" }
  attrs: {
    name: "rel"
    mandatory: true
    value_casei: "preload"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  attrs: {
    name: "imagesrcset"
    value_url: {
      protocol: "http"
      protocol: "https"
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: { name: "imagesizes" }
  attr_lists: "common-link-attrs"
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# Allowlisted CSS provider
tags: {
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "LINK"
  spec_name: "link rel=stylesheet for amp-story-1.0 css"
  descriptive_name: "link rel=stylesheet for amp-story-1.0 css"
  mandatory_parent: "HEAD"
  attr_lists: "nonce-attr"
  attrs: { name: "crossorigin" }  # SRI attribute (https://www.w3.org/TR/SRI/)
  attrs: {
    name: "href"
    mandatory: true
    value: "https://cdn.ampproject.org/v0/amp-story-1.0.css"
    value: "https://cdn.ampproject.org/lts/v0/amp-story-1.0.css"
    value: "https://ampjs.org/v0/amp-story-1.0.css"
    value: "https://ampjs.org/lts/v0/amp-story-1.0.css"
  }
  attrs: { name: "integrity" }  # SRI attribute (https://www.w3.org/TR/SRI/)
  attrs: { name: "media" }
  attrs: {
    name: "rel"
    mandatory: true
    value_casei: "stylesheet"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  attrs: {
    name: "type"
    value_casei: "text/css"
  }
  attrs: {
    name: "amp-extension"
    mandatory: true
    value_casei: "amp-story"
  }
}
# Allowlisted font providers
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "LINK"
  spec_name: "link rel=stylesheet for fonts"
  descriptive_name: "link rel=stylesheet for fonts"
  named_id: LINK_FONT_STYLESHEET
  mandatory_parent: "HEAD"
  attr_lists: "nonce-attr"
  attrs: { name: "async" }
  attrs: { name: "crossorigin" }  # SRI attribute (https://www.w3.org/TR/SRI/)
  attrs: {
    name: "href"
    mandatory: true
    value_regex: "https://cdn\\.materialdesignicons\\.com/"
                 "([0-9]+\\.?)+/css/materialdesignicons\\.min\\.css|"
                 "https://cloud\\.typography\\.com/"
                 "[0-9]*/[0-9]*/css/fonts\\.css|"
                 "https://fast\\.fonts\\.net/.*|"
                 "https://fonts\\.googleapis\\.com/css2?\\?.*|"
                 "https://fonts\\.googleapis\\.com/icon\\?.*|"
                 "https://fonts\\.googleapis\\.com/earlyaccess/.*\\.css|"
                 "https://maxcdn\\.bootstrapcdn\\.com/font-awesome/"
                 "([0-9]+\\.?)+/css/font-awesome\\.min\\.css(\\?.*)?|"
                 "https://(use|pro|kit)\\.fontawesome\\.com/releases/v([0-9]+\\.?)+"
                 "/css/[0-9a-zA-Z-]+\\.css|"
                 "https://(use|pro|kit)\\.fontawesome\\.com/[0-9a-zA-Z-]+\\.css|"
                 "https://use\\.typekit\\.net/[\\w\\p{L}\\p{N}_]+\\.css|"
                 "https://cdnjs\\.cloudflare\\.com/ajax/libs/font-awesome/"
                 "([0-9]+\\.?)+/css/[0-9a-zA-Z-]+\\.min\\.css"

  }
  attrs: { name: "integrity" }  # SRI attribute (https://www.w3.org/TR/SRI/)
  attrs: { name: "media" }
  attrs: {
    name: "rel"
    mandatory: true
    value_casei: "stylesheet"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  attrs: {
    name: "type"
    value_casei: "text/css"
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#custom-fonts"
}
# itemprop=sameAs is allowed per schema.org, needs not be in head
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "LINK"
  spec_name: "link itemprop=sameAs"
  descriptive_name: "link itemprop=sameAs"
  attrs: {
    name: "href"
    mandatory: true
  }
  attrs: {
    name: "itemprop"
    mandatory: true
    value_casei: "sameas"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  attr_lists: "common-link-attrs"
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# rel= isn't mandatory when itemprop= is present.
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "LINK"
  spec_name: "link itemprop="
  descriptive_name: "link itemprop="
  attrs: {
    name: "href"
    mandatory: true
  }
  attrs: {
    name: "itemprop"
    mandatory: true
  }
  attr_lists: "common-link-attrs"
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# rel= isn't mandatory when property= is present.
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "LINK"
  spec_name: "link property="
  descriptive_name: "link property="
  attrs: {
    name: "href"
    mandatory: true
  }
  attrs: {
    name: "property"
    mandatory: true
  }
  attr_lists: "common-link-attrs"
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# 4.2.5 the meta element
# Charset must be utf8, and a specific viewport is required.
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "META"
  spec_name: "meta charset=utf-8"
  descriptive_name: "meta charset=utf-8"
  mandatory: true
  mandatory_parent: "HEAD"
  unique: true
  attrs: {
    dispatch_key: NAME_DISPATCH
    name: "charset"
    mandatory: true
    value_casei: "utf-8"
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta name=viewport"
  descriptive_name: "meta name=viewport"
  mandatory: true
  mandatory_parent: "HEAD"
  unique: true
  attrs: {
    name: "content"
    mandatory: true
    value_properties: {
      properties: { name: "width" mandatory: true value: "device-width" }
      properties: { name: "height" }
      properties: { name: "initial-scale" }
      properties: { name: "minimum-scale" }
      properties: { name: "maximum-scale" }
      properties: { name: "shrink-to-fit" }
      properties: { name: "user-scalable" }
      properties: { name: "viewport-fit" }
    }
  }
  attrs: {
    name: "name"
    mandatory: true
    value: "viewport"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
# This tag is a hack to tell IE 10 to use its modern rendering engine as opposed
# to the IE8 engine. So it's explicitly allowed.
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta http-equiv=X-UA-Compatible"
  descriptive_name: "meta http-equiv=X-UA-Compatible"
  mandatory_ancestor: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
    value_properties: {
      properties: { name: "ie" value: "edge" }
      properties: { name: "chrome" value: "1" }
    }
  }
  attrs: {
    name: "http-equiv"
    mandatory: true
    value_casei: "x-ua-compatible"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# Tag specific to apple-itunes-app installs, see also <amp-app-banner>.
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta name=apple-itunes-app"
  mandatory_parent: "HEAD"
  satisfies_condition: "amp-app-banner data source"
  attrs: {
    name: "content"
    mandatory: true
    value_regex: ".*app-id=.*"
  }
  attrs: {
    name: "name"
    value_casei: "apple-itunes-app"
    mandatory: true
    dispatch_key: NAME_VALUE_DISPATCH
  }

  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# AMP & AMP4ADS metadata, name=amp-experiments-opt-in
# https://github.com/ampproject/amphtml/blob/main/tools/experiments/README.md
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta name=amp-experiments-opt-in"
  mandatory_parent: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-experiments-opt-in"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
# AMP metadata, name=amp-3p-iframe-src
tags: {
  html_format: AMP
  tag_name: "META"
  spec_name: "meta name=amp-3p-iframe-src"
  mandatory_parent: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
    value_url: {
      protocol: "https"
    }
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-3p-iframe-src"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  spec_url: "https://amp.dev/documentation/components/amp-ad/"
}
# AMP metadata, name=amp-consent-blocking
tags: {
  html_format: AMP
  tag_name: "META"
  spec_name: "meta name=amp-consent-blocking"
  mandatory_parent: "HEAD"
  satisfies_condition: "meta name=amp-consent-blocking"
  unique: true
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-consent-blocking"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
# AMP metadata, name=amp-experiment-token
# Related to AMP Origin Experiments
tags: {
  html_format: AMP
  tag_name: "META"
  spec_name: "meta name=amp-experiment-token"
  mandatory_parent: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-experiment-token"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  # Disabled because there are no active origin experiments; uncomment when
  # there is at least one corresponding `requires` clause.
  # satisfies_condition: "amp-experiment-token"
}
# AMP metadata, name=amp-link-variable-allowed-origin
# https://github.com/ampproject/amphtml/issues/8132
tags: {
  html_format: AMP
  tag_name: "META"
  spec_name: "meta name=amp-link-variable-allowed-origin"
  mandatory_parent: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-link-variable-allowed-origin"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
# AMP metadata, name=amp-google-client-id-api
tags: {
  html_format: AMP
  tag_name: "META"
  spec_name: "meta name=amp-google-clientid-id-api"
  mandatory_parent: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-google-client-id-api"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
# AMP metadata, name=amp-ad-doubleclick-sra
# Enables SRA for amp-ad doubleclick Fast Fetch
tags: {
  html_format: AMP
  tag_name: "META"
  spec_name: "meta name=amp-ad-doubleclick-sra"
  mandatory_parent: "HEAD"
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-ad-doubleclick-sra"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
# AMP metadata, name=amp-list-load-more
tags: {
  html_format: AMP
  tag_name: "META"
  spec_name: "meta name=amp-list-load-more"
  mandatory_parent: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-list-load-more"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
# AMP metadata, name=amp-recaptcha-input
tags: {
  html_format: AMP
  tag_name: "META"
  spec_name: "meta name=amp-recaptcha-input"
  mandatory_parent: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-recaptcha-input"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
# AMP metadata, name=amp-script-src
tags: {
  html_format: AMP
  tag_name: "META"
  spec_name: "meta name=amp-script-src"
  mandatory_parent: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-script-src"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
# AMP4ADS metadata, name=amp4ads-id
# https://github.com/ampproject/amphtml/issues/7730
tags: {
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta name=amp4ads-id"
  mandatory_parent: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp4ads-id"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "META"
  spec_name: "meta name= and content="
  attrs: { name: "content" }
  attrs: { name: "itemprop" }  # itemprop is non-standard, but commonly seen.
  # The validator accepts any name="..." attribute values except
  # for a few specific name values which have more specific rules above or
  # are altogether disallowed.
  attrs: {
    name: "name"
    disallowed_value_regex: "(^|\\s)("
        "amp-.*|"
        "amp4ads-.*|"
        "apple-itunes-app|"
        "content-disposition|"
        "revisit-after|"
        "viewport"
        ")(\\s|$)"
  }
  attrs: { name: "media" } # For varying theme-color.
  attrs: { name: "property" }  # property is non-standard, but commonly seen.
  # scheme is used by Dublin Core, see issue #13993
  attrs: { name: "scheme" }
}
# This is redundant with meta charset, but also harmless as long as it's
# set to utf-8.
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta http-equiv=Content-Type"
  mandatory_ancestor: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
    value_casei: "text/html; charset=utf-8"
  }
  attrs: {
    name: "http-equiv"
    mandatory: true
    value_casei: "content-type"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# http-equiv content-language tag
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta http-equiv=content-language"
  mandatory_ancestor: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "http-equiv"
    mandatory: true
    value_casei: "content-language"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# http-equiv pics-label tag
# https://www.w3.org/PICS/
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta http-equiv=pics-label"
  mandatory_ancestor: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "http-equiv"
    mandatory: true
    value_casei: "pics-label"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# http-equiv imagetoolbar tag
# https://msdn.microsoft.com/en-us/library/ms532986(v=vs.85).aspx
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta http-equiv=imagetoolbar"
  mandatory_ancestor: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "http-equiv"
    mandatory: true
    value_casei: "imagetoolbar"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# http-equiv content-style-type
# https://www.w3.org/TR/REC-html40/present/styles#h-14.2.1
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta http-equiv=Content-Style-Type"
  mandatory_ancestor: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
    value_casei: "text/css"
  }
  attrs: {
    name: "http-equiv"
    mandatory: true
    value_casei: "content-style-type"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# http-equiv content-script-type
# https://www.w3.org/TR/html4/interact/scripts#h-18.2.2.1
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta http-equiv=Content-Script-Type"
  mandatory_ancestor: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
    value_casei: "text/javascript"
  }
  attrs: {
    name: "http-equiv"
    mandatory: true
    value_casei: "content-script-type"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# http-equiv origin-trial tag
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta http-equiv=origin-trial"
  mandatory_ancestor: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "http-equiv"
    mandatory: true
    value_casei: "origin-trial"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# http-equiv resource-type
# http://www.metatags.info/meta_http_equiv_resource_type
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta http-equiv=resource-type"
  mandatory_ancestor: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "http-equiv"
    mandatory: true
    value_casei: "resource-type"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# http-equiv x-dns-prefetch-control
# https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-DNS-Prefetch-Control
tags: {
  html_format: AMP
  tag_name: "META"
  spec_name: "meta http-equiv=x-dns-prefetch-control"
  mandatory_ancestor: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
    value_casei: "off"
    value_casei: "on"
  }
  attrs: {
    name: "http-equiv"
    mandatory: true
    value_casei: "x-dns-prefetch-control"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#html-tags"
}
# AMP metadata, name=amp-ad-enable-refresh
# Enables Refresh for amp-ad doubleclick Fast Fetch
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta name=amp-ad-enable-refresh"
  mandatory_ancestor: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-ad-enable-refresh"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
# AMP metadata, name=amp-to-amp-navigation
# Enables AMP-to-AMP navigation
tags: {
  html_format: AMP
  tag_name: "META"
  spec_name: "meta name=amp-to-amp-navigation"
  mandatory_parent: "HEAD"
  unique: true
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-to-amp-navigation"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
# AMP metadata, name=amp-cta-type
# Specifies the Single Page Story Ad call to action enum
tags: {
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta name=amp-cta-type"
  mandatory_parent: "HEAD"
  unique: true
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-cta-type"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
# AMP metadata, name=amp-cta-url
# Specifies the Single Page Story Ad call to action outlink
tags: {
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta name=amp-cta-url"
  mandatory_parent: "HEAD"
  unique: true
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-cta-url"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
# AMP metadata, name=amp-cta-landing-page-type
# Specifies the Single Page Story Ad landing page type
tags: {
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta name=amp-cta-landing-page-type"
  mandatory_parent: "HEAD"
  unique: true
  attrs: {
    name: "content"
    mandatory: true
    value_casei: "amp"
    value_casei: "nonamp"
    value_casei: "story"
  }
  attrs: {
    name: "name"
    mandatory: true
    value_casei: "amp-cta-landing-page-type"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
# AMP metadata, name=amp4ads-vars-*
# Allows advertisers to pass information from creatives
# to be included in amp-ad-metadata.
tags: {
  html_format: AMP4ADS
  tag_name: "META"
  spec_name: "meta name=amp4ads-vars-*"
  mandatory_parent: "HEAD"
  attrs: {
    name: "content"
    mandatory: true
  }
  attrs: {
    name: "name"
    mandatory: true
    value_regex: "amp4ads-vars-.+"
  }
}
# 4.2.6 The style
# See `validator-css.protoascii`.

# 4.3 Sections
# 4.3.1 The body element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "BODY"
  mandatory: true
  unique: true
  mandatory_parent: "HTML"
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
# 4.3.2 The article element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "ARTICLE"
}
# 4.3.3 The section element
attr_lists: {
  name: "poool-access-attrs"
  attrs: {
    name: "poool-access-preview"
    requires_extension: "amp-access-poool"
  }
  attrs: {
    name: "poool-access-content"
    requires_extension: "amp-access-poool"
  }
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "SECTION"
  disallowed_ancestor: "AMP-ACCORDION"
  attr_lists: "poool-access-attrs"
}
tags: {
  html_format: AMP4EMAIL
  tag_name: "SECTION"
  spec_name: "section (AMP4EMAIL)"
  disallowed_ancestor: "AMP-ACCORDION"
}
# 4.3.4 The nav element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "NAV"
}
# 4.3.5 The aside element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "ASIDE"
}
# 4.3.6 The h1, h2, h3, h4, h5, and h6 elements
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "H1"
  attrs: { name: "align" }
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "H2"
  attrs: { name: "align" }
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "H3"
  attrs: { name: "align" }
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "H4"
  attrs: { name: "align" }
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "H5"
  attrs: { name: "align" }
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "H6"
  attrs: { name: "align" }
}
# 4.3 7 The header element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "HEADER"
}
# 4.3 7 The footer element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "FOOTER"
}
# 4.3 7 The address element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "ADDRESS"
}

# 4.4 Grouping Content
# 4.4.1 The p element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "P"
  attrs: { name: "align" }
}
# 4.4.2 The hr element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "HR"
}
# 4.4.3 The pre element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "PRE"
}
# 4.4.4 The blockquote element
attr_lists: {
  name: "cite-attr"
  attrs: {
    name: "cite"
    value_url: {
      protocol: "http"
      protocol: "https"
      allow_empty: true
    }
    disallowed_value_regex: "__amp_source_origin"
  }
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "BLOCKQUOTE"
  attrs: { name: "align" }
  attr_lists: "cite-attr"
}
# 4.4.5 The ol element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "OL"
  attrs: {
    name: "reversed"
    value: ""
  }
  attrs: {
    name: "start"
    value_regex: "[0-9]*"
  }
  attrs: {
    name: "type"
    value_regex: "[1AaIi]"
  }
}
# 4.4.6 The ul element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "UL"
}
# 4.4.7 The li element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "LI"
  attrs: {
    name: "value"
    value_regex: "[0-9]*"
  }
}
# 4.4.8 The dl element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "DL"
}
# 4.4.9 The dt element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "DT"
}
# 4.4.10 The dd element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "DD"
}
# 4.4.11 The figure element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "FIGURE"
}
# 4.4.12 The figcaption element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "FIGCAPTION"
}
# 4.4.13 The div element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "DIV"
  attrs: { name: "align" }
}
# 4.4.14 The main element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "MAIN"
}

# 4.5 Text-level semantics
# 4.5.1 The a element
attr_lists: {
  # https://github.com/ampproject/amphtml/issues/35067
  name: "click-attributions"
  attrs: { name: "attributiondestination" }
  attrs: { name: "attributionexpiry" }
  attrs: { name: "attributionreportto" }
  attrs: { name: "attributionsourceeventid" }
  attrs: { name: "attributionsourceid" }
  attrs: { name: "conversiondestination" }
  attrs: { name: "impressiondata" }
  attrs: { name: "impressionexpiry" }
  attrs: { name: "reportingorigin" }
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "A"
  attrs: {
    name: "attributionsrc"
    value_url: {
      protocol: "https"
      allow_empty: true
    }
  }
  attrs: { name: "border" }  # Not valid html5 but commonly used and supported.
  attrs: { name: "download" }
  attrs: {
    name: "href"
    value_url: {
      # When updating this list, make sure to also update bind-validator.js.
      protocol: "ftp"
      protocol: "geo"
      protocol: "http"
      protocol: "https"
      protocol: "mailto"
      protocol: "maps"
      # Allowlisting additional commonly observed third party
      # protocols which should be safe.
      # BiP Messenger
      protocol: "bip"
      # Blackberry messenger
      # (http://devblog.blackberry.com/2015/02/cross-platform-sharing-with-bbm/)
      protocol: "bbmi"
      protocol: "chrome"
      # IOS over-the-air app installation
      # (https://github.com/nifcblm/AHPP-iOS-App/wiki/How-to-distribute-enterprise-iOS-App)
      protocol: "itms-services"
      protocol: "facetime"
      protocol: "fb-me"
      protocol: "fb-messenger"
      protocol: "feed"
      protocol: "intent"
      # Line messenger (https://media.line.me/howto/en/)
      protocol: "line"
      # (https://docs.microsoft.com/en-us/windows/uwp/launch-resume/launch-default-app#microsoft-edge-uri-scheme)
      protocol: "microsoft-edge"
      protocol: "skype"
      protocol: "sms"
      protocol: "snapchat"
      protocol: "tel"
      protocol: "tg"
      protocol: "threema"
      protocol: "twitter"
      protocol: "viber"
      protocol: "webcal"
      protocol: "web+mastodon"  # See GitHub issue #14793
      protocol: "wh"
      protocol: "whatsapp"
      allow_empty: true
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: { name: "hreflang" }
  attrs: { name: "media" }
  attrs: { name: "referrerpolicy" }
  attrs: {
    name: "rel"
    # There are a wide variety of link rel attribute values used in the wild as
    # this attribute is used as meta-data for any html client such as search
    # engines. Unfortunately, there are also a number of attribute values which
    # have behavioral impacts in modern browsers. A few places where these are
    # loosely documented include:
    # - http://microformats.org/wiki/existing-rel-values
    # - http://www.iana.org/assignments/link-relations/link-relations.xhtml
    # - https://html.spec.whatwg.org/#linkTypes
    # We denylist a few specific values which have browser behavior that could
    # negatively impact performance.
    # TODO(gregable): This could be improved such that the error message would
    # report which value in a list is the one causing problems.
    disallowed_value_regex: "(^|\\s)("  # Values are space separated.
        "components|"
        "dns-prefetch|"
        "import|"
        "manifest|"
        "preconnect|"
        "prefetch|"
        "preload|"
        "prerender|"
        "serviceworker|"
        "stylesheet|"  # Only allowed for link tags, specific req's for AMP.
        "subresource"
        ")(\\s|$)"
  }
  attrs: {
    name: "role"
    implicit: true
  }
  attrs: {
    name: "show-tooltip"
    value: "auto"
    value: "true"
  }
  attrs: {
    name: "tabindex"
    implicit: true
  }
  attrs: {
    name: "target"
    value: "_blank"
    value: "_self"
    value: "_top"
  }
  attrs: {
    name: "type"
    value_casei: "text/html"
    value_casei: "application/rss+xml"
  }
  attr_lists: "click-attributions"
  attr_lists: "name-attr"
  attr_lists: "private-click-measurement-attributes"
  # <amp-bind>
  attrs: { name: "[href]" }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#links"
}
# AMP4EMAIL restricts the use of mustache delimiters in href. The only allowed
# protocols for href are http, https and mailto. Relative urls are disallowed.
tags: {
  html_format: AMP4EMAIL
  tag_name: "A"
  spec_name: "A (AMP4EMAIL)"
  attrs: { name: "border" }  # Not valid html5 but commonly used and supported.
  attrs: {
    name: "href"
    value_url: {
      protocol: "http"
      protocol: "https"
      protocol: "mailto"
      protocol: "tel"
      allow_relative: false
    }
    # Opening doubly curly brackets {{ (these are mustache delimiters) can only
    # appear at the beginning of the attribute's value. Likewise closing doubly
    # curly brackets }} can only appear at the end of the attribute's value.
    # Furthermore unbalanced delimiters are not allowed.
    # Additionally section mustache delimiters, i.e., {{#, {{^, {{/ are
    # disallowed.
    disallowed_value_regex: "__amp_source_origin|"
        "(.|\\s){{|"    # Opening delimiter can only appear at the beginning.
        "}}(.|\\s)|"    # Closing delimiter can only appear at the end.
        "^{{.*[^}][^}]$|"    # Delimiters must be balanced.
        "^[^{][^{].*}}$|"    # Delimiters must be balanced.
        "^}}|"    # Also caught by the requirements on balanced delimiters.
        "{{$|"    # Also caught by the requirements on balanced delimiters.
        "{{#|"    # Section delimiters are disallowed.
        "{{/|"    # Section delimiters are disallowed.
        "{{\\^"   # Section delimiters are disallowed.
  }
  attrs: { name: "hreflang" }
  # TODO(gregable): Specify the set of allowed media queries.
  attrs: { name: "media" }
  attrs: {
    name: "role"
    implicit: true
  }
  attrs: {
    name: "tabindex"
    implicit: true
  }
  attrs: {
    name: "target"
    value: "_blank"
  }
  attrs: {
    name: "type"
    value_casei: "text/html"
  }
}
# Private Click Measurement attributes for anchor tags.
# See https://github.com/ampproject/amphtml/issues/35067
attr_lists {
  name: "private-click-measurement-attributes"
  attrs: { name: "attributiondestination" }
  attrs: { name: "attributionexpiry" }
  attrs: { name: "attributionreportto" }
  attrs: { name: "attributionsourceeventid" }
  attrs: { name: "attributionsourceid" }
  attrs: { name: "conversiondestination" }
  attrs: { name: "impressiondata" }
  attrs: { name: "impressionexpiry" }
  attrs: { name: "reportingorigin" }
}

# 4.5.2 The em element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "EM"
}
# 4.5.3 The strong element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "STRONG"
}
# 4.5.4 The small element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "SMALL"
}
# 4.5.5 The s element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "S"
}
# 4.5.6 The cite element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "CITE"
}
# 4.5.7 The q element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "Q"
  attr_lists: "cite-attr"
}
# 4.5.8 The dfn element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "DFN"
}
# 4.5.9 The abbr element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "ABBR"
}
# 4.5.10 The data element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "DATA"
}
# 4.5.11 The time element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "TIME"
  attrs: {
    name: "datetime"
  }
  attrs: {
    name: "pubdate"
    value: ""
  }
}
# 4.5.12 The code element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "CODE"
}
# 4.5.13 The var element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "VAR"
}
# 4.5.14 The samp element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "SAMP"
}
# 4.5.15 The kbd element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "KBD"
}
# 4.5.16 The sub and sup elements
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "SUB"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "SUP"
}
# 4.5.17 The i element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "I"
}
# 4.5.18 The b element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "B"
}
# 4.5.19 The u element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "U"
}
# 4.5.20 The mark element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "MARK"
}
# 4.5.21 The ruby element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "RUBY"
}
# 4.5.22 The rb element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "RB"
}
# 4.5.23 The rt element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "RT"
}
# 4.5.24 The rtc element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "RTC"
}
# 4.5.25 The rp element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "RP"
}
# 4.5.26 The bdi element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "BDI"
}
# 4.5.27 The bdo element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "BDO"
  attrs: { name: "dir" }
}
# 4.5.28 The span element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "SPAN"
}
# 4.5.29 The br element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "BR"
}
# 4.5.30 The wbr element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "WBR"
}

# 4.6 Edits
# 4.6.1 The ins element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "INS"
  # https://developer.mozilla.org/en-US/docs/Web/HTML/Element/ins
  # These attributes have specific formatting, but as they are metadata
  # that can't hurt performance, rendering or security, we don't validate
  # the values.
  attrs { name: "datetime" }
  attr_lists: "cite-attr"
}
# 4.6.2 The del element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "DEL"
  # https://developer.mozilla.org/en-US/docs/Web/HTML/Element/del
  # These attributes have specific formatting, but as they are metadata
  # that can't hurt performance, rendering or security, we don't validate
  # the values.
  attrs { name: "datetime" }
  attr_lists: "cite-attr"
}

# 4.7 Embedded Content
# AMP HTML allows embedded content only via its own tags (e.g. amp-img), with
# the exception of tags inside of a <noscript> or <amp-story-player> ancestor
# and transformed amp-img.
# 4.7.1 The img element
attr_lists: {
  name: "img-attrs"
  attrs: {
    name: "align"
    value_casei: "top"
    value_casei: "middle"
    value_casei: "bottom"
    value_casei: "left"
    value_casei: "right"
  }
  attrs: { name: "alt" }
  attrs: { name: "border" }
  attrs: {
    name: "crossorigin"
    value_casei: "anonymous"
    value_casei: "use-credentials"
  }
  attrs: {
    name: "fetchpriority"
    value_casei: "high"
    value_casei: "low"
    value_casei: "auto"
  }
  attrs: { name: "height" }
  attrs: { name: "hspace" }
  # https://developers.google.com/web/updates/2019/02/priority-hints
  attrs: {
    name: "importance"
    value_casei: "high"
    value_casei: "low"
    value_casei: "auto"
  }
  attrs: { name: "ismap" }
  attrs: {
    name: "loading"
    value_casei: "lazy"
  }  # Not yet part of the html spec
  attrs: { name: "name" }
  attrs: {
    name: "referrerpolicy"
    value_casei: "no-referrer"
    value_casei: "no-referrer-when-downgrade"
    value_casei: "origin"
    value_casei: "origin-when-cross-origin"
    value_casei: "same-origin"
    value_casei: "strict-origin"
    value_casei: "strict-origin-when-cross-origin"
    value_casei: "unsafe-url"
  }
  attrs: { name: "usemap" }
  attrs: { name: "vspace" }
  attrs: { name: "width" }
}
tags: {
  html_format: AMP
  tag_name: "IMG"
  spec_name: "Standard Img"
  descriptive_name: "img"
  disallowed_ancestor: "AMP-IMG"
  disallowed_ancestor: "AMP-STORY"
  attrs: {
    name: "decoding"
    value_casei: "async"
  }
  attr_lists: "img-attrs"
  attr_lists: "mandatory-src-or-srcset"
}
tags: {
  html_format: AMP
  tag_name: "IMG"
  spec_name: "Hero Img"
  descriptive_name: "img"
  disallowed_ancestor: "AMP-IMG"
  disallowed_ancestor: "AMP-STORY"
  attrs: {
    name: "data-hero"
    mandatory: true
    dispatch_key: NAME_DISPATCH
  }
  attrs: {
    name: "decoding"
    value_casei: "async"
  }
  attrs: {
    name: "sizes"
  }
  attr_lists: "img-attrs"
  attr_lists: "mandatory-src-or-srcset"
}
tags: {
  html_format: AMP
  tag_name: "IMG"
  spec_name: "Img using srcset"
  descriptive_name: "img"
  disallowed_ancestor: "AMP-IMG"
  disallowed_ancestor: "AMP-STORY"
  attrs: {
    name: "decoding"
    value_casei: "async"
  }
  attrs: {
    name: "sizes"
  }
  attr_lists: "img-attrs"
  attr_lists: "mandatory-src-or-srcset"
}
tags: {
  html_format: AMP
  tag_name: "IMAGE"
  spec_name: "Standard Image"
  descriptive_name: "img"
  disallowed_ancestor: "AMP-IMG"
  disallowed_ancestor: "AMP-STORY"
  attrs: {
    name: "decoding"
    value_casei: "async"
  }
  attr_lists: "img-attrs"
  attr_lists: "mandatory-src-or-srcset"
}
tags: {
  html_format: AMP
  tag_name: "IMAGE"
  spec_name: "Hero Image"
  descriptive_name: "img"
  disallowed_ancestor: "AMP-IMG"
  disallowed_ancestor: "AMP-STORY"
  attrs: {
    name: "data-hero"
    mandatory: true
    dispatch_key: NAME_DISPATCH
  }
  attrs: {
    name: "decoding"
    value_casei: "async"
  }
  attrs: {
    name: "sizes"
  }
  attr_lists: "img-attrs"
  attr_lists: "mandatory-src-or-srcset"
}
tags: {
  html_format: AMP
  tag_name: "IMAGE"
  spec_name: "Image using srcset"
  disallowed_ancestor: "AMP-IMG"
  disallowed_ancestor: "AMP-STORY"
  descriptive_name: "img"
  attrs: {
    name: "decoding"
    value_casei: "async"
  }
  attr_lists: "img-attrs"
  attr_lists: "mandatory-src-or-srcset"
  attrs: {
    name: "sizes"
  }
}
tags: {
  html_format: AMP  # Disallowed in AMP4ADS because <noscript> is disallowed.
  tag_name: "IMG"
  spec_name: "noscript > img"
  descriptive_name: "img"
  mandatory_ancestor: "NOSCRIPT"
  mandatory_ancestor_suggested_alternative: "AMP-IMG"
  attrs: { name: "attribution" }
  attrs: {
    name: "decoding"
    value_casei: "async"
    value_casei: "auto"
    value_casei: "sync"
  }
  attrs: { name: "intrinsicsize" }  # Not yet part of the html spec
  attrs: { name: "sizes" }
  attr_lists: "img-attrs"
  attr_lists: "mandatory-src-or-srcset"
  spec_url: "https://amp.dev/documentation/components/amp-img/"
}
# 4.7.2 The iframe element
tags: {
  html_format: AMP  # Disallowed in AMP4ADS because <noscript> is disallowed.
  tag_name: "IFRAME"
  mandatory_ancestor: "NOSCRIPT"
  mandatory_ancestor_suggested_alternative: "AMP-IFRAME"
  spec_url: "https://amp.dev/documentation/components/amp-iframe/"
  attrs: {
    name: "frameborder"
    value: "0"
    value: "1"
  }
  attrs: { name: "height" }
  attrs: { name: "referrerpolicy" }
  attrs: {
    name: "resizable"
    value: ""
  }
  attrs: {
    name: "sandbox"
  }
  attrs: {
    name: "scrolling"
    value: "auto"
    value: "yes"
    value: "no"
  }
  attrs: {
    name: "src"
    mandatory_oneof: "['src', 'srcdoc']"
    value_url: {
      protocol: "data"
      protocol: "https"
      allow_relative: false
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: {
    name: "srcdoc"
    mandatory_oneof: "['src', 'srcdoc']"
  }
  attrs: {
    name: "width"
  }
  attr_lists: "name-attr"
}
# 4.7.6 The video element
# Only allowed in noscript tags. Otherwise use amp-video.
tags: {
  html_format: AMP  # Disallowed in AMP4ADS because <noscript> is disallowed.
  tag_name: "VIDEO"
  mandatory_ancestor: "NOSCRIPT"
  mandatory_ancestor_suggested_alternative: "AMP-VIDEO"
  attrs: { name: "autoplay" }
  attrs: { name: "controls" }
  attrs: { name: "height" }
  attrs: { name: "loop" }
  attrs: {
    name: "muted"
    deprecation: "autoplay"
    deprecation_url: "https://amp.dev/documentation/components/amp-video/"
  }
  attrs: { name: "playsinline" }
  attrs: { name: "poster" }
  attrs: { name: "preload" }
  attrs: {
    name: "src"
    value_url: {
      protocol: "data"
      protocol: "https"
      allow_relative: false
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: { name: "width" }
  spec_url: "https://amp.dev/documentation/components/amp-video/"
}
# 4.7.7 The audio element
# Allowed in noscript tags and inside amp-audio for server side rendering.
tags: {
  html_format: AMP  # Disallowed in AMP4ADS because <noscript> is disallowed.
  tag_name: "AUDIO"
  mandatory_ancestor: "NOSCRIPT"
  mandatory_ancestor_suggested_alternative: "AMP-AUDIO"
  attrs: { name: "autoplay" }
  attrs: { name: "controls" }
  attrs: { name: "loop" }
  attrs: { name: "muted" }
  attrs: { name: "preload" }
  attrs: {
    name: "src"
    value_url: {
      protocol: "data"
      protocol: "https"
      allow_relative: false
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  spec_url: "https://amp.dev/documentation/components/amp-audio/"
}
tags: {
  html_format: AMP  # Disallowed in AMP4ADS because <noscript> is disallowed.
  tag_name: "AUDIO"
  mandatory_ancestor: "AMP-AUDIO"
  spec_name: "amp-audio > audio"
  attrs: { name: "controls" }
  spec_url: "https://amp.dev/documentation/components/amp-audio/"
}
# 4.7.7 The picture element
# Only allowed in noscript tags which support img tags.
tags: {
  html_format: AMP
  tag_name: "PICTURE"
  mandatory_parent: "NOSCRIPT"
  spec_url: "https://amp.dev/documentation/components/amp-img/"
}
# 4.7.8 The source element
tags: {
  html_format: AMP
  tag_name: "SOURCE"
  spec_name: "picture > source"
  mandatory_parent: "PICTURE"  # PICTURE is only allowed inside NOSCRIPT
  attrs: { name: "media" }
  attrs: { name: "sizes" }
  attrs: {
    name: "srcset"
    value_url: {
      protocol: "data"
      protocol: "http"
      protocol: "https"
      allow_relative: true
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: { name: "type" }
  spec_url: "https://amp.dev/documentation/components/amp-img/"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "SOURCE"
  spec_name: "amp-video > source"
  mandatory_parent: "AMP-VIDEO"
  attrs: { name: "media" }
  attrs: {
    name: "src"
    value_url: {
      protocol: "https"
      allow_relative: true  # Will be set to false at a future date.
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: { name: "type" }
  # <amp-bind>
  attrs: { name: "[src]" }
  attrs: { name: "[type]" }
  spec_url: "https://amp.dev/documentation/components/amp-video/"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "SOURCE"
  spec_name: "amp-audio > source"
  mandatory_parent: "AMP-AUDIO"
  attrs: { name: "media" }
  attrs: {
    name: "src"
    value_url: {
      protocol: "https"
      allow_relative: true  # Will be set to false at a future date.
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: { name: "type" }
  # <amp-bind>
  attrs: { name: "[src]" }
  attrs: { name: "[type]" }
  spec_url: "https://amp.dev/documentation/components/amp-audio/"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "SOURCE"
  spec_name: "audio > source"
  mandatory_parent: "AUDIO"
  attrs: { name: "media" }
  attrs: {
    name: "src"
    mandatory: true
    value_url: {
      protocol: "https"
      allow_relative: true  # Will be set to false at a future date.
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: {
    name: "type"
    mandatory: true
  }
  spec_url: "https://amp.dev/documentation/components/amp-audio/"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "SOURCE"
  spec_name: "video > source"
  mandatory_parent: "VIDEO"
  attrs: { name: "media" }
  attrs: {
    name: "src"
    mandatory: true
    value_url: {
      protocol: "https"
      allow_relative: true  # Will be set to false at a future date.
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: {
    name: "type"
    mandatory: true
  }
  spec_url: "https://amp.dev/documentation/components/amp-video/"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "SOURCE"
  spec_name: "amp-ima-video > source"
  mandatory_parent: "AMP-IMA-VIDEO"
  requires_extension: "amp-ima-video"
  attrs: { name: "media" }
  attrs: {
    name: "src"
    value_url: {
      protocol: "https"
      allow_relative: true  # Will be set to false at a future date.
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: { name: "type" }
  # <amp-bind>
  attrs: { name: "[src]" }
  attrs: { name: "[type]" }
}
# 4.7.8 The track element
# We have two attr_list variants to encode the requirement that if
# the attribute kind has the value 'subtitles', then the tag must
# also have a srclang attribute. The first attr_list does not allow
# kind=subtitles, but srclang is optional. The second attr_list
# mandates kind=subtitles and srclang attributes.
attr_lists: {
  name: "track-attrs-no-subtitles"
  attrs: {
    name: "default"
    value: ""
  }
  attrs: {
    name: "kind"
    value: "captions"
    value: "chapters"
    value: "descriptions"
    value: "metadata"
  }
  attrs: { name: "label" }
  attrs: {
    name: "src"
    mandatory: true
    value_url: {
      protocol: "https"
      allow_relative: false
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: { name: "srclang" }
}
attr_lists: {
  name: "track-attrs-subtitles"
  attrs: {
    name: "default"
    value: ""
  }
  attrs: {
    name: "kind"
    mandatory: true
    value_casei: "subtitles"
  }
  attrs: { name: "label" }
  attrs: {
    name: "src"
    mandatory: true
    value_url: {
      protocol: "https"
      allow_relative: false
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: {
    name: "srclang"
    mandatory: true
  }
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "TRACK"
  spec_name: "audio > track"
  mandatory_parent: "AUDIO"
  attr_lists: "track-attrs-no-subtitles"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "TRACK"
  spec_name: "audio > track[kind=subtitles]"
  mandatory_parent: "AUDIO"
  attr_lists: "track-attrs-subtitles"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "TRACK"
  spec_name: "video > track"
  mandatory_parent: "VIDEO"
  attr_lists: "track-attrs-no-subtitles"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "TRACK"
  spec_name: "video > track[kind=subtitles]"
  mandatory_parent: "VIDEO"
  attr_lists: "track-attrs-subtitles"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "TRACK"
  spec_name: "amp-audio > track"
  mandatory_parent: "AMP-AUDIO"
  # <amp-bind>
  attrs: { name: "[label]" }
  attrs: { name: "[src]" }
  attrs: { name: "[srclang]" }
  attr_lists: "track-attrs-no-subtitles"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "TRACK"
  spec_name: "amp-audio > track[kind=subtitles]"
  mandatory_parent: "AMP-AUDIO"
  # <amp-bind>
  attrs: { name: "[label]" }
  attrs: { name: "[src]" }
  attrs: { name: "[srclang]" }
  attr_lists: "track-attrs-subtitles"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "TRACK"
  spec_name: "amp-video > track"
  mandatory_parent: "AMP-VIDEO"
  # <amp-bind>
  attrs: { name: "[label]" }
  attrs: { name: "[src]" }
  attrs: { name: "[srclang]" }
  attr_lists: "track-attrs-no-subtitles"
}
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "TRACK"
  spec_name: "amp-video > track[kind=subtitles]"
  mandatory_parent: "AMP-VIDEO"
  # <amp-bind>
  attrs: { name: "[label]" }
  attrs: { name: "[src]" }
  attrs: { name: "[srclang]" }
  attr_lists: "track-attrs-subtitles"
}
tags: {
  html_format: AMP
  tag_name: "TRACK"
  spec_name: "amp-ima-video > track"
  mandatory_parent: "AMP-IMA-VIDEO"
  # <amp-bind>
  attrs: { name: "[label]" }
  attrs: { name: "[src]" }
  attrs: { name: "[srclang]" }
  attr_lists: "track-attrs-no-subtitles"
}
tags: {
  html_format: AMP
  tag_name: "TRACK"
  spec_name: "amp-ima-video > track[kind=subtitles]"
  mandatory_parent: "AMP-IMA-VIDEO"
  # <amp-bind>
  attrs: { name: "[label]" }
  attrs: { name: "[src]" }
  attrs: { name: "[srclang]" }
  attr_lists: "track-attrs-subtitles"
  spec_url: "https://amp.dev/documentation/components/amp-ima-video/"
}

# 4.7.15 SVG
# See validator-svg.protoascii.

# 4.8 Links
# Links are a concept, rather than a tag. See tagspecs for "LINK", "A", etc.

# 4.8.11 The canvas element
# See extensions/amp-mustache/validator-amp-script.protoascii

# 4.9 Tabular data
# 4.9.1 The table element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "TABLE"
  attrs: { name: "align" }  # Not valid html5 but commonly used and supported.
  attrs: { name: "bgcolor" }  # Not valid html5 but commonly used and supported.
  attrs: {  # Not valid html5 but commonly used and supported.
    name: "border"
    value: "0"
    value: "1"
  }
  attrs: { name: "cellpadding" }  # Not valid html5 but commonly used and supported.
  attrs: { name: "cellspacing" }  # Not valid html5 but commonly used and supported.
  attrs: {
    disabled_by: "amp4email"
    name: "sortable"
  }
  attrs: { name: "width" }  # Not valid html5 but commonly used and supported.
}
# 4.9.2 The caption element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "CAPTION"
}
# 4.9.3 The colgroup element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "COLGROUP"
  attrs: { name: "span" }
}
# 4.9.4 The col element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "COL"
  attrs: { name: "span" }
}
# 4.9.5 The tbody element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "TBODY"
}
# 4.9.6 The thead element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "THEAD"
}
# 4.9.7 The tfoot element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "TFOOT"
}
# 4.9.8 The tr element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "TR"
  # These attributes are not supported in HTML5, but are widely supported and
  # commonly found.
  attrs: { name: "align" }
  attrs: { name: "bgcolor" }
  attrs: { name: "height" }
  attrs: { name: "valign" }
}
# 4.9.9 The td element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "TD"
  attrs: { name: "align" }  # Not valid html5 but commonly used and supported.
  attrs: { name: "bgcolor" }  # Not valid html5 but commonly used and supported.
  attrs: { name: "colspan" }
  attrs: { name: "headers" }
  attrs: { name: "height" }  # Not valid html5 but commonly used and supported.
  attrs: { name: "rowspan" }
  attrs: { name: "valign" }  # Not valid html5 but commonly used and supported.
  attrs: { name: "width" }  # Not valid html5 but commonly used and supported.
}
# 4.9.10 The th element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "TH"
  attrs: { name: "abbr" }
  attrs: { name: "align" }  # Not valid html5 but commonly used and supported.
  attrs: { name: "bgcolor" }  # Not valid html5 but commonly used and supported.
  attrs: { name: "colspan" }
  attrs: { name: "headers" }
  attrs: { name: "height" }  # Not valid html5 but commonly used and supported.
  attrs: { name: "rowspan" }
  attrs: { name: "scope" }
  attrs: {
    disabled_by: "amp4email"
    name: "sorted"
  }
  attrs: { name: "valign" }  # Not valid html5 but commonly used and supported.
  attrs: { name: "width" }  # Not valid html5 but commonly used and supported.
}

# 4.10 Forms
# Form elements are allowed only when amp-form extension script is included
# with the exception of the button element which is always allowed.
# 4.10.3 The form element
tags {  # <form method=GET ...>
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "FORM"
  spec_name: "FORM [method=GET]"
  requires_extension: "amp-form"
  disallowed_ancestor: "AMP-APP-BANNER"
  attrs: { name: "accept" }
  attrs: { name: "accept-charset" }
  # For method=GET forms, we require `action` and allow `action-xhr`.
  attrs: {
    name: "action"
    mandatory: true
    value_url: {
      protocol: "https"
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: {
    name: "action-xhr"
    value_url: {
      protocol: "https"
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: { name: "autocomplete" }
  attrs: {
    name: "custom-validation-reporting"
    value: "as-you-go"
    value: "interact-and-submit"
    value: "show-all-on-submit"
    value: "show-first-on-submit"
  }
  attrs: { name: "enctype" }
  attrs: {
    name: "method"
    # Default value is GET, so if method attribute is missing,
    # it matches this tagspec.
    value_casei: "get"
  }
  attrs: { name: "novalidate" }
  attrs: {
    name: "target"
    mandatory: true
    value_casei: "_blank"
    value_casei: "_top"
  }
  attrs: {
    name: "verify-xhr"
    value_url: {
      protocol: "https"
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: { name: "xssi-prefix" }
  attr_lists: "form-name-attr"
}
tags {  # <form method=POST ...>
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "FORM"
  spec_name: "FORM [method=POST]"
  requires_extension: "amp-form"
  disallowed_ancestor: "AMP-APP-BANNER"
  attrs: { name: "accept" }
  attrs: { name: "accept-charset" }
  # For method=POST forms, we require `action-xhr` and disallow `action`.
  attrs: {
    name: "action-xhr"
    mandatory: true
    value_url: {
      protocol: "https"
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: { name: "autocomplete" }
  attrs: {
    name: "custom-validation-reporting"
    value: "as-you-go"
    value: "interact-and-submit"
    value: "show-all-on-submit"
    value: "show-first-on-submit"
  }
  attrs: { name: "enctype" }
  attrs: {
    name: "method"
    mandatory: true
    value_casei: "post"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  attrs: { name: "novalidate" }
  # The target attribute has no effect, and should not be in POST forms.
  # However, in the past it was required, so disallowing it would break many
  # pages. See: https://github.com/ampproject/amphtml/issues/5607
  attrs: {
    name: "target"
    value_casei: "_blank"
    value_casei: "_top"
  }
  attrs: {
    name: "verify-xhr"
    value_url: {
      protocol: "https"
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: { name: "xssi-prefix" }
  attr_lists: "form-name-attr"
}
# AMP4EMAIL allows action-xhr and disallows action attribute. It also disallows
# the use of mustache templates in action-xhr. The only allowed
# protocol for action-xhr is https. Relative urls are disallowed. It also
# disallows the name attribute as the name attribute is prone to DOM clobbering.
tags {  # <form method=GET ...>
  html_format: AMP4EMAIL
  tag_name: "FORM"
  spec_name: "FORM [method=GET] (AMP4EMAIL)"
  requires_extension: "amp-form"
  attrs: { name: "accept" }
  attrs: { name: "accept-charset" }
  # AMP4EMAIL only allows 'action-xhr'.
  attrs: {
    name: "action-xhr"
    value_url: {
      protocol: "https"
      allow_relative: false
    }
    disallowed_value_regex: "__amp_source_origin|"
        "{{|}}"    # Mustache is disallowed in action-xhr.
  }
  attrs: { name: "autocomplete" }
  attrs: {
    name: "custom-validation-reporting"
    value: "as-you-go"
    value: "interact-and-submit"
    value: "show-all-on-submit"
    value: "show-first-on-submit"
  }
  attrs: { name: "enctype" }
  attrs: {
    name: "method"
    # Default value is GET, so if method attribute is missing,
    # it matches this tagspec.
    value_casei: "get"
  }
  attrs: { name: "novalidate" }
  attrs: { name: "xssi-prefix" }
}
tags {  # <form method=POST ...>
  html_format: AMP4EMAIL
  tag_name: "FORM"
  spec_name: "FORM [method=POST] (AMP4EMAIL)"
  requires_extension: "amp-form"
  attrs: { name: "accept" }
  attrs: { name: "accept-charset" }
  # For method=POST forms, we require `action-xhr` and disallow `action`.
  attrs: {
    name: "action-xhr"
    mandatory: true
    value_url: {
      protocol: "https"
      allow_relative: false
    }
    disallowed_value_regex: "__amp_source_origin|"
        "{{|}}"    # Mustache is disallowed in action-xhr.
  }
  attrs: { name: "autocomplete" }
  attrs: {
    name: "custom-validation-reporting"
    value: "as-you-go"
    value: "interact-and-submit"
    value: "show-all-on-submit"
    value: "show-first-on-submit"
  }
  attrs: { name: "enctype" }
  attrs: {
    name: "method"
    mandatory: true
    value_casei: "post"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  attrs: { name: "novalidate" }
  attrs: { name: "xssi-prefix" }
}
# Will add verify state template if requested by users
tags {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "DIV"
  spec_name: "FORM DIV [verify-error]"
  mandatory_ancestor: "FORM"
  attrs: { name: "align" }
  attrs: {
    name: "verify-error"
    mandatory: true
  }
}
tags {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "DIV"
  spec_name: "FORM DIV [verify-error][template]"
  mandatory_ancestor: "FORM"
  attrs: { name: "align" }
  attrs: {
    name: "verify-error"
    mandatory: true
  }
  attrs: {
    name: "template"
    mandatory: true
  }
}
tags {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "DIV"
  spec_name: "FORM DIV [submitting]"
  mandatory_ancestor: "FORM"
  attrs: { name: "align" }
  attrs: {
    name: "submitting"
    mandatory: true
  }
}
tags {
  html_format: AMP
  html_format: AMP4ADS
  # AMP4EMAIL is omitted. There is additional latency in rendering A4E
  # templates, which reduces the time available to render the template during
  # the submitting state.
  tag_name: "DIV"
  spec_name: "FORM DIV [submitting][template]"
  mandatory_ancestor: "FORM"
  attrs: { name: "align" }
  attrs: {
    name: "submitting"
    mandatory: true
  }
  attrs: {
    name: "template"
    mandatory: true
  }
}
tags {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "DIV"
  spec_name: "FORM DIV [submit-success]"
  mandatory_ancestor: "FORM"
  attrs: { name: "align" }
  attrs: {
    name: "submit-success"
    mandatory: true
  }
}
tags {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "DIV"
  spec_name: "FORM DIV [submit-success][template]"
  mandatory_ancestor: "FORM"
  attrs: { name: "align" }
  attrs: {
    name: "submit-success"
    mandatory: true
  }
  attrs: {
    name: "template"
    mandatory: true
  }
}
tags {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "DIV"
  spec_name: "FORM DIV [submit-error]"
  mandatory_ancestor: "FORM"
  attrs: { name: "align" }
  attrs: {
    name: "submit-error"
    mandatory: true
  }
}
tags {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "DIV"
  spec_name: "FORM DIV [submit-error][template]"
  mandatory_ancestor: "FORM"
  attrs: { name: "align" }
  attrs: {
    name: "submit-error"
    mandatory: true
  }
  attrs: {
    name: "template"
    mandatory: true
  }
}
attr_lists: {
  name: "input-common-attr"
  attrs: { name: "accept" }
  attrs: { name: "accesskey" }
  attrs: { name: "autocomplete" }
  attrs: {
    disabled_by: "amp4email"
    name: "autofocus"
  }
  attrs: { name: "checked" }
  attrs: { name: "disabled" }
  attrs: { name: "height" }
  attrs: {
    disabled_by: "amp4email"
    name: "inputmode"
  }
  attrs: {
    disabled_by: "amp4email"
    name: "list"
  }
  attrs: {
    disabled_by: "amp4email"
    name: "enterkeyhint"
  }
  attrs: { name: "max" }
  attrs: { name: "maxlength" }
  attrs: { name: "min" }
  attrs: { name: "minlength" }
  attrs: { name: "multiple" }
  attrs: { name: "pattern" }
  attrs: { name: "placeholder" }
  attrs: { name: "readonly" }
  attrs: { name: "required" }
  attrs: {
    disabled_by: "amp4email"
    name: "selectiondirection"
  }
  attrs: { name: "size" }
  attrs: { name: "spellcheck" }
  attrs: { name: "step" }
  attrs: { name: "tabindex" }
  attrs: { name: "value" }
  attrs: { name: "width" }
  # <amp-bind>
  attrs: {
    disabled_by: "amp4email"
    name: "[accept]"
  }
  attrs: {
    disabled_by: "amp4email"
    name: "[accesskey]"
  }
  attrs: { name: "[autocomplete]" }
  attrs: { name: "[checked]" }
  attrs: { name: "[disabled]" }
  attrs: { name: "[height]" }
  attrs: {
    disabled_by: "amp4email"
    name: "[inputmode]"
  }
  attrs: { name: "[max]" }
  attrs: { name: "[maxlength]" }
  attrs: { name: "[min]" }
  attrs: { name: "[minlength]" }
  attrs: { name: "[multiple]" }
  attrs: { name: "[pattern]" }
  attrs: { name: "[placeholder]" }
  attrs: { name: "[readonly]" }
  attrs: { name: "[required]" }
  attrs: {
    disabled_by: "amp4email"
    name: "[selectiondirection]"
  }
  attrs: { name: "[size]" }
  attrs: { name: "[spellcheck]" }
  attrs: { name: "[step]" }
  attrs: { name: "[value]" }
  attrs: { name: "[width]" }
}
# 4.10.4 The label element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "LABEL"
  attrs: { name: "for" }
  spec_url: "https://amp.dev/documentation/components/amp-form/"
}
# 4.10.5 The input element.
# The input tag is also defined by extensions/amp-inputmask/validator-amp-inputmask.protoascii
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "INPUT"
  attrs: {
    disabled_by: "amp4email"
    name: "no-verify"
    value: ""
  }
  attrs: {
    name: "type"
    disallowed_value_regex: "(^|\\s)("  # Values are space separated.
        "file|"
        "image|"
        "password|"
        ")(\\s|$)"
  }
  attrs: {
    disabled_by: "amp4email"
    name: "[type]"
  }
  attr_lists: "input-common-attr"
  attr_lists: "name-attr"
  spec_url: "https://amp.dev/documentation/components/amp-form/"
}
tags: {
  html_format: AMP
  tag_name: "INPUT"
  spec_name: "INPUT [type=file]"
  attrs: {
    disabled_by: "amp4email"
    name: "capture"
    value: ""
  }
  attrs: {
    disabled_by: "amp4email"
    name: "no-verify"
    value: ""
  }
  attrs: {
    name: "type"
    value_casei: "file"
    mandatory: true
    dispatch_key: NAME_VALUE_DISPATCH
  }
  attrs: {
    disabled_by: "amp4email"
    name: "[type]"
  }
  attr_lists: "input-common-attr"
  attr_lists: "name-attr"
  mandatory_ancestor: "FORM [method=POST]"
  spec_url: "https://amp.dev/documentation/components/amp-form/"
}
tags: {
  html_format: AMP
  tag_name: "INPUT"
  spec_name: "INPUT [type=password]"
  attrs: {
    name: "type"
    value_casei: "password"
    mandatory: true
    dispatch_key: NAME_VALUE_DISPATCH
  }
  attrs: {
    disabled_by: "amp4email"
    name: "[type]"
  }
  attr_lists: "input-common-attr"
  attr_lists: "name-attr"
  mandatory_ancestor: "FORM [method=POST]"
  spec_url: "https://amp.dev/documentation/components/amp-form/"
}
tags: {
  html_format: AMP
  tag_name: "INPUT"
  spec_name: "INPUT [type=image]"
  attrs: {
    name: "type"
    value_casei: "image"
    mandatory: true
    dispatch_key: NAME_VALUE_DISPATCH
  }
  attrs: {
    disabled_by: "amp4email"
    name: "[type]"
  }
  attrs: {
    name: "src"
    mandatory: true
    value_url: {
      protocol: "data"
      protocol: "http"
      protocol: "https"
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attr_lists: "input-common-attr"
  attr_lists: "name-attr"
  mandatory_ancestor: "FORM [method=POST]"
  spec_url: "https://amp.dev/documentation/components/amp-form/"
}
# 4.10.6 The button element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "BUTTON"
  attrs: {
    name: "disabled"
    value: ""
  }
  attrs: {
    name: "role"
    implicit: true
  }
  attrs: {
    name: "tabindex"
    implicit: true
  }
  attrs: { name: "type" }
  attrs: { name: "value" }
  # <amp-bind>
  attrs: { name: "[disabled]" }
  attrs: {
    disabled_by: "amp4email"
    name: "[type]"
  }
  attrs: { name: "[value]" }
  attr_lists: "name-attr"
}
# Button variant specifically supporting <amp-app-banner> tag with the
# open-button attribute.
tags: {
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "BUTTON"
  spec_name: "amp-app-banner button[open-button]"
  satisfies_condition: "amp-app-banner button[open-button]"
  mandatory_ancestor: "AMP-APP-BANNER"
  attrs: {
    name: "open-button"
    value: ""
  }
  attrs: {
    name: "role"
    implicit: true
  }
  attrs: {
    name: "tabindex"
    implicit: true
  }
  attrs: { name: "type" }
  attrs: { name: "value" }
  attr_lists: "name-attr"
}
# 4.10.7 The select element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "SELECT"
  attrs: {
    disabled_by: "amp4email"
    name: "autofocus"
  }
  attrs: { name: "disabled" }
  attrs: { name: "multiple" }
  attrs: {
    disabled_by: "amp4email"
    name: "no-verify"
    value: ""
  }
  attrs: { name: "required" }
  attrs: { name: "size" }
  # <amp-bind>
  attrs: {
    disabled_by: "amp4email"
    name: "[autofocus]"
  }
  attrs: { name: "[disabled]" }
  attrs: { name: "[multiple]" }
  attrs: { name: "[required]" }
  attrs: { name: "[size]" }
  attr_lists: "name-attr"
  spec_url: "https://amp.dev/documentation/components/amp-form/"
}
# 4.10.8 The datalist element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "DATALIST"
  spec_url: "https://amp.dev/documentation/components/amp-form/"
}
# 4.10.9 The optgroup element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "OPTGROUP"
  mandatory_parent: "SELECT"
  attrs: { name: "disabled" }
  attrs: { name: "label" }
  # <amp-bind>
  attrs: { name: "[disabled]" }
  attrs: { name: "[label]" }
  spec_url: "https://amp.dev/documentation/components/amp-form/"
}
# 4.10.10 The option element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "OPTION"
  attrs: { name: "disabled" }
  attrs: { name: "label" }
  attrs: { name: "selected" }
  attrs: { name: "value" }
  # <amp-bind>
  attrs: { name: "[disabled]" }
  attrs: { name: "[label]" }
  attrs: { name: "[selected]" }
  attrs: { name: "[value]" }
  spec_url: "https://amp.dev/documentation/components/amp-form/"
}
# 4.10.11 The textarea element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "TEXTAREA"
  attrs: { name: "autocomplete" }
  attrs: {
    name: "autoexpand"
    requires_extension: "amp-form"
  }
  attrs: {
    disabled_by: "amp4email"
    name: "autofocus"
  }
  attrs: { name: "cols" }
  attrs: { name: "disabled" }
  attrs: { name: "maxlength" }
  attrs: { name: "minlength" }
  attrs: {
    disabled_by: "amp4email"
    name: "no-verify"
    value: ""
  }
  attrs: { name: "pattern" }
  attrs: { name: "placeholder" }
  attrs: { name: "readonly" }
  attrs: { name: "required" }
  attrs: { name: "rows" }
  attrs: {
    disabled_by: "amp4email"
    name: "selectiondirection"
  }
  attrs: {
    disabled_by: "amp4email"
    name: "selectionend"
  }
  attrs: {
    disabled_by: "amp4email"
    name: "selectionstart"
  }
  attrs: { name: "spellcheck" }
  attrs: { name: "wrap" }
  # <amp-bind>
  attrs: { name: "[autocomplete]" }
  attrs: {
    disabled_by: "amp4email"
    name: "[autofocus]"
  }
  attrs: { name: "[cols]" }
  attrs: { name: "[defaulttext]" }
  attrs: { name: "[disabled]" }
  attrs: { name: "[maxlength]" }
  attrs: { name: "[minlength]" }
  attrs: { name: "[pattern]" }
  attrs: { name: "[placeholder]" }
  attrs: { name: "[readonly]" }
  attrs: { name: "[required]" }
  attrs: { name: "[rows]" }
  attrs: {
    disabled_by: "amp4email"
    name: "[selectiondirection]"
  }
  attrs: {
    disabled_by: "amp4email"
    name: "[selectionend]"
  }
  attrs: {
    disabled_by: "amp4email"
    name: "[selectionstart]"
  }
  attrs: { name: "[spellcheck]" }
  attrs: { name: "[wrap]" }
  attr_lists: "name-attr"
  spec_url: "https://amp.dev/documentation/components/amp-form/"
}
# 4.10.13 The output element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "OUTPUT"
  attrs: { name: "for" }
  attrs: { name: "form" }
  attr_lists: "name-attr"
}
# 4.10.14 The progress element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "PROGRESS"
  attrs: { name: "max" }
  attrs: { name: "value" }
}
# 4.10.15 The meter element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "METER"
  attrs: { name: "high" }
  attrs: { name: "low" }
  attrs: { name: "max" }
  attrs: { name: "min" }
  attrs: { name: "optimum" }
  attrs: { name: "value" }
}
# 4.10.16 The fieldset element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "FIELDSET"
  attrs: { name: "disabled" }
  # <amp-bind>
  attrs: { name: "[disabled]" }
  attr_lists: "name-attr"
}
# 4.10.17 The legend element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "LEGEND"
}

# 4.11 (HTML5.3) Interactive elements
# 4.11.1 (HTML5.3) The details element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "DETAILS"
  attrs: {
    name: "open"
    value: ""
  }
  attrs: { name: "[open]" }
}
# 4.11.2 (HTML5.3) The summary element
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "SUMMARY"
  mandatory_parent: "DETAILS"
}

# 4.11 Scripting
# 4.11.1 The script element
# Only the amphtml script, custom extensions and the LD/JSON or TEXT/PLAIN
# description are allowed.
# Note that the type TEXT/PLAIN description is define in
# validator-amp-mustache.protoascii.

# The three tagspecs below all handle the runtime engine script. They
# enforce that exactly one runtime script must be included. This tagspec is
# for the standard runtime, while the one below it is an identical spec but for
# the LTS runtime, with the only difference being the src attribute. The third
# is the corresponding spec for AMP4EMAIL.
attr_lists: {
  name: "amphtml-engine-attrs"
  attrs: {
    name: "async"
    mandatory: true
    value: ""
  }
  attrs: {
    name: "crossorigin"
    value: "anonymous"
  }
  attrs: {
    name: "type"
    value_casei: "text/javascript"
  }
}
attr_lists: {
  name: "amphtml-module-engine-attrs"
  attrs: {
    name: "async"
    mandatory: true
    value: ""
  }
  attrs: {
    name: "crossorigin"
    mandatory: true
    value: "anonymous"
  }
  attrs: {
    name: "type"
    mandatory: true
    value_casei: "module"
    dispatch_key: NAME_VALUE_DISPATCH
  }
}
attr_lists: {
  name: "amphtml-nomodule-engine-attrs"
  attrs: {
    name: "async"
    mandatory: true
    value: ""
  }
  attrs: {
    name: "crossorigin"
    value: "anonymous"
  }
  attrs: {
    name: "nomodule"
    mandatory: true
    value: ""
  }
  attrs: {
    name: "type"
    value_casei: "text/javascript"
  }
}
tags: {
  html_format: AMP
  disabled_by: "transformed"
  tag_name: "SCRIPT"
  spec_name: "amphtml engine script"
  descriptive_name: "amphtml engine script"
  satisfies_condition: "amphtml javascript runtime (v0.js)"
  requires_condition: "style[amp-boilerplate]"
  requires_condition: "noscript > style[amp-boilerplate]"
  unique: true
  mandatory_parent: "HEAD"
  attr_lists: "nonce-attr"
  attr_lists: "amphtml-engine-attrs"
  attrs: {
    name: "src"
    mandatory: true
    value: "https://cdn.ampproject.org/v0.js"
    value: "https://ampjs.org/v0.js"
  }
  cdata: {
    disallowed_cdata_regex: {
      regex: "."
      error_message: "contents"
    }
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
tags: {
  # The transformed variant is the same except does not require the boilerplate,
  # given that it may have been removed during transformation.
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "SCRIPT"
  spec_name: "amphtml engine script (transformed)"
  descriptive_name: "amphtml engine script"
  satisfies_condition: "amphtml javascript runtime (v0.js)"
  unique: true
  mandatory_parent: "HEAD"
  attr_lists: "nonce-attr"
  attr_lists: "amphtml-engine-attrs"
  attrs: {
    name: "src"
    mandatory: true
    value: "https://cdn.ampproject.org/v0.js"
    value: "https://ampjs.org/v0.js"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  cdata: {
    disallowed_cdata_regex: {
      regex: "."
      error_message: "contents"
    }
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
tags: {
  html_format: AMP
  disabled_by: "transformed"
  tag_name: "SCRIPT"
  spec_name: "amphtml engine script (LTS)"
  descriptive_name: "amphtml engine script"
  satisfies_condition: "amphtml javascript runtime (v0.js)"
  requires_condition: "style[amp-boilerplate]"
  requires_condition: "noscript > style[amp-boilerplate]"
  unique: true
  mandatory_parent: "HEAD"
  attr_lists: "nonce-attr"
  attr_lists: "amphtml-engine-attrs"
  attrs: {
    name: "src"
    mandatory: true
    value: "https://cdn.ampproject.org/lts/v0.js"
    value: "https://ampjs.org/lts/v0.js"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  cdata: {
    disallowed_cdata_regex: {
      regex: "."
      error_message: "contents"
    }
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
tags: {
  # The transformed variant is the same except does not require the boilerplate,
  # given that it may have been removed during transformation.
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "SCRIPT"
  spec_name: "amphtml engine script (LTS) (transformed)"
  descriptive_name: "amphtml engine script"
  satisfies_condition: "amphtml javascript runtime (v0.js)"
  unique: true
  mandatory_parent: "HEAD"
  attr_lists: "nonce-attr"
  attr_lists: "amphtml-engine-attrs"
  attrs: {
    name: "src"
    mandatory: true
    value: "https://cdn.ampproject.org/lts/v0.js"
    value: "https://ampjs.org/lts/v0.js"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  cdata: {
    disallowed_cdata_regex: {
      regex: "."
      error_message: "contents"
    }
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
tags: {
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "SCRIPT"
  spec_name: "amphtml module engine script"
  descriptive_name: "amphtml module engine script"
  satisfies_condition: "amphtml javascript runtime (v0.js)"
  unique: true
  mandatory_parent: "HEAD"
  satisfies_condition: "amphtml module engine script"
  requires_condition: "amphtml nomodule engine script"
  attr_lists: "nonce-attr"
  attr_lists: "amphtml-module-engine-attrs"
  attrs: {
    name: "src"
    mandatory: true
    value: "https://cdn.ampproject.org/v0.mjs"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  cdata: {
    whitespace_only: true
  }
  # TODO(b/167681900): update spec_url to cover these script release versions
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
tags: {
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "SCRIPT"
  spec_name: "amphtml nomodule engine script"
  descriptive_name: "amphtml nomodule engine script"
  satisfies_condition: "amphtml javascript runtime (v0.js)"
  unique: true
  mandatory_parent: "HEAD"
  satisfies_condition: "amphtml nomodule engine script"
  requires_condition: "amphtml module engine script"
  attr_lists: "nonce-attr"
  attr_lists: "amphtml-nomodule-engine-attrs"
  attrs: {
    name: "src"
    mandatory: true
    value: "https://cdn.ampproject.org/v0.js"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  cdata: {
    whitespace_only: true
  }
  # TODO(b/167681900): update spec_url to cover these script release versions
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
tags: {
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "SCRIPT"
  spec_name: "amphtml module LTS engine script"
  descriptive_name: "amphtml module LTS engine script"
  satisfies_condition: "amphtml javascript runtime (v0.js)"
  unique: true
  mandatory_parent: "HEAD"
  satisfies_condition: "amphtml module LTS engine script"
  requires_condition: "amphtml nomodule LTS engine script"
  attr_lists: "nonce-attr"
  attr_lists: "amphtml-module-engine-attrs"
  attrs: {
    name: "src"
    mandatory: true
    value: "https://cdn.ampproject.org/lts/v0.mjs"
    value: "https://ampjs.org/lts/v0.mjs"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  cdata: {
    whitespace_only: true
  }
  # TODO(b/167681900): update spec_url to cover these script release versions
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
tags: {
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "SCRIPT"
  spec_name: "amphtml nomodule LTS engine script"
  descriptive_name: "amphtml nomdule LTS engine script"
  satisfies_condition: "amphtml javascript runtime (v0.js)"
  unique: true
  mandatory_parent: "HEAD"
  satisfies_condition: "amphtml nomodule LTS engine script"
  requires_condition: "amphtml module LTS engine script"
  attr_lists: "nonce-attr"
  attr_lists: "amphtml-nomodule-engine-attrs"
  attrs: {
    name: "src"
    mandatory: true
    value: "https://cdn.ampproject.org/lts/v0.js"
    value: "https://ampjs.org/lts/v0.js"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  cdata: {
    whitespace_only: true
  }
  # TODO(b/167681900): update spec_url to cover these script release versions
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
tags: {
  html_format: AMP4EMAIL
  tag_name: "SCRIPT"
  spec_name: "amphtml engine script [AMP4EMAIL]"
  descriptive_name: "amphtml engine script"
  satisfies_condition: "amphtml javascript runtime (v0.js)"
  requires_condition: "style[amp-boilerplate]"
  mandatory: true
  unique: true
  mandatory_parent: "HEAD"
  attr_lists: "nonce-attr"
  attr_lists: "amphtml-engine-attrs"
  attrs: {
    name: "src"
    mandatory: true
    value: "https://cdn.ampproject.org/v0.js"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  cdata: {
    disallowed_cdata_regex: {
      regex: "."
      error_message: "contents"
    }
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
tags: {
  html_format: AMP4ADS
  tag_name: "SCRIPT"
  spec_name: "amp4ads engine script"
  descriptive_name: "amphtml engine script"
  satisfies_condition: "amphtml javascript runtime (v0.js)"
  requires_condition: "style[amp-boilerplate]"
  mandatory: true
  unique: true
  mandatory_parent: "HEAD"
  attr_lists: "nonce-attr"
  attr_lists: "amphtml-engine-attrs"
  attrs: {
    name: "src"
    mandatory: true
    value: "https://cdn.ampproject.org/amp4ads-v0.js"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  cdata: {
    disallowed_cdata_regex: {
      regex: "."
      error_message: "contents"
    }
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amphtml/#required-markup"
}
# JSON Linked Data
tags: {
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "SCRIPT"
  spec_name: "script type=application/ld+json"
  descriptive_name: "script type=application/ld+json"
  attr_lists: "nonce-attr"
  attrs: {
    name: "type"
    mandatory: true
    value_casei: "application/ld+json"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  cdata: {
    disallowed_cdata_regex: {
      regex: "<!--"
      error_message: "html comments"
    }
  }
}
# AMP RTC (Real Time Config)
tags: {
  html_format: AMP
  tag_name: "SCRIPT"
  spec_name: "script id=amp-rtc"
  unique: true
  mandatory_parent: "HEAD"
  attr_lists: "nonce-attr"
  attrs: {
    name: "id"
    mandatory: true
    value_casei: "amp-rtc"
    dispatch_key: NAME_VALUE_DISPATCH
  }
  attrs: {
    name: "type"
    mandatory: true
    value_casei: "application/json"
  }
  cdata: {
    disallowed_cdata_regex: {
      regex: "<!--"
      error_message: "html comments"
    }
  }
}
# AMP IMA VIDEO
tags: {
  html_format: AMP
  tag_name: "SCRIPT"
  spec_name: "amp-ima-video > script[type=application/json]"
  descriptive_name: "script type=application/ld+json"
  mandatory_parent: "AMP-IMA-VIDEO"
  attrs: {
    name: "type"
    mandatory: true
    value_casei: "application/json"
    dispatch_key: NAME_VALUE_PARENT_DISPATCH
  }
  cdata: {
    disallowed_cdata_regex: {
      regex: "<!--"
      error_message: "html comments"
    }
  }
}
# Enables early styling on fast failure to load v0.js or v0.mjs. See GitHub #22543.
tags: {
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "SCRIPT"
  spec_name: "script amp-onerror (v0.js or v0.mjs)"
  descriptive_name: "script amp-onerror"
  unique: true
  mandatory_parent: "HEAD"
  attrs: {
    name: "amp-onerror"
    value: ""
    mandatory: true
    dispatch_key: NAME_VALUE_DISPATCH
  }
  cdata: {
    # Only valid if contents are exactly either of these:
    # [].slice.call(document.querySelectorAll("script[src*='/v0.js'],script[src*='/v0.mjs']")).forEach(function(s){s.onerror=function(){document.querySelector('style[amp-boilerplate]').textContent=''}})
    # document.querySelector("script[src*='/v0.js']").onerror=function(){document.querySelector('style[amp-boilerplate]').textContent=''}
    cdata_regex: "\\[]\\.slice\\.call\\(document\\.querySelectorAll\\(\"script\\[src\\*='\\/v0\\.js'],script\\[src\\*='\\/v0\\.mjs']\"\\)\\)\\.forEach\\(function\\(s\\){s\\.onerror=function\\(\\){document\\.querySelector\\('style\\[amp-boilerplate]'\\)\\.textContent=''}}\\)|"
                 "document\\.querySelector\\(\"script\\[src\\*='\\/v0\\.js']\"\\)\\.onerror=function\\(\\){document\\.querySelector\\('style\\[amp-boilerplate]'\\)\\.textContent=''}"
  }
}

# Dynamic Viewport (dvh) Polyfill when amp-story-1.0.css is Server Side Rendered.
tags: {
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "SCRIPT"
  spec_name: "script amp-story-dvh-polyfill"
  descriptive_name: "script amp-story-dvh-polyfill"
  unique: true
  mandatory_parent: "HEAD"
  attrs: {
    name: "amp-story-dvh-polyfill"
    value: ""
    mandatory: true
    dispatch_key: NAME_VALUE_DISPATCH
  }
  cdata: {
    # Only valid if contents is exactly:
    # "use strict";if(!self.CSS||!CSS.supports||!CSS.supports("height:1dvh")){function e(){document.documentElement.style.setProperty("--story-dvh",innerHeight/100+"px","important")}addEventListener("resize",e,{passive:!0}),e()}
    cdata_regex: "\"use strict\";if\\(!self\\.CSS\\|\\|!CSS\\.supports\\|\\|!CSS\\.supports\\(\"height:1dvh\"\\)\\)\\{function e\\(\\)\\{document\\.documentElement\\.style\\.setProperty\\(\"--story-dvh\",innerHeight/100\\+\"px\",\"important\"\\)\\}addEventListener\\(\"resize\",e,\\{passive:!0\\}\\),e\\(\\)\\}"
  }
}

# Enables early styling on fast failure to load v0.js. See GitHub #22543.
tags: {
  html_format: AMP
  tag_name: "SCRIPT"
  spec_name: "script amp-onerror (v0.js)"
  descriptive_name: "script amp-onerror"
  unique: true
  mandatory_parent: "HEAD"
  attrs: {
    name: "amp-onerror"
    value: ""
    mandatory: true
    dispatch_key: NAME_VALUE_DISPATCH
  }
  cdata: {
    mandatory_cdata: "document.querySelector(\"script[src*='/v0.js']\").onerror=function(){document.querySelector('style[amp-boilerplate]').textContent=''}"
  }
}

# Specific script tags for custom elements and runtime imports.
# 4.11.2 The noscript element
tags: {
  html_format: AMP
  tag_name: "NOSCRIPT"
  spec_name: "noscript enclosure for amp style tags"
  mandatory_parent: "HEAD"
  child_tags {
    child_tag_name_oneof: "STYLE"
    mandatory_min_num_child_tags: 1
  }
  spec_url: "https://amp.dev/documentation/guides-and-tutorials/learn/spec/amp-boilerplate/?format=websites"
}
# We allow noscript in the body to contain tags otherwise disallowed by AMP.
tags: {
  html_format: AMP
  tag_name: "NOSCRIPT"
  # Noscript inside of noscript has strange parsing semantics in browsers and
  # isn't really helping anyone anyway.
  mandatory_ancestor: "BODY"
  disallowed_ancestor: "NOSCRIPT"
}
# 4.11.3 The template element
# See extensions/amp-mustache/validator-amp-mustache.protoascii.

# 11 Obsolete features
# 11.2 Non-conforming features
tags: {
  html_format: AMP
  tag_name: "ACRONYM"
}
tags: {
  html_format: AMP
  tag_name: "BIG"
}
tags: {
  html_format: AMP
  tag_name: "CENTER"
}
tags: {
  html_format: AMP
  tag_name: "DIR"
}
tags: {
  html_format: AMP
  tag_name: "HGROUP"
}
tags: {
  html_format: AMP
  tag_name: "LISTING"
}
tags: {
  html_format: AMP
  tag_name: "MULTICOL"
}
tags: {
  html_format: AMP
  tag_name: "NEXTID"
}
tags: {
  html_format: AMP
  tag_name: "NOBR"
}
tags: {
  html_format: AMP
  tag_name: "SPACER"
}
tags: {
  html_format: AMP
  tag_name: "STRIKE"
}
tags: {
  html_format: AMP
  tag_name: "TT"
}

# Some additional tags, microformats, allowances.

# The slot element.
# https://developer.mozilla.org/en-US/docs/Web/HTML/Element/slot
tags: {
  html_format: AMP
  tag_name: "SLOT"
  attr_lists: "name-attr"
}

# This tag is a preserved indicator for documents created in microsoft word.
# They do not render.
tags: {
  html_format: AMP
  tag_name: "O:P"
}

# Tags and attributes specific to AMP HTML.
# AMP Custom elements require a "src" or a "srcset" attribute,
# having both is also allowed.
attr_lists: {
  name: "mandatory-src-or-srcset"
  attrs: {
    name: "src"
    alternative_names: "srcset"
    mandatory: true
    value_url: {
      protocol: "data"
      protocol: "http"
      protocol: "https"
    }
    disallowed_value_regex: "__amp_source_origin"
  }
}
# In AMP4EMAIL Custom elements require a "src" attribute. Unlike AMP-HTML,
# srcset is disallowed. In addition "src" is not bindable in AMP4EMAIL and the
# only accepted protocol is https. Finally the AMP4EMAIL restrictions on
# mustache on href appear here as well.
attr_lists: {
  name: "mandatory-src-amp4email"
  attrs: {
    name: "src"
    mandatory: true
    value_url: {
      protocol: "https"
      allow_relative: false
    }
    # Opening doubly curly brackets {{ (these are mustache delimiters) can only
    # appear at the beginning of the attribute's value. Likewise closing doubly
    # curly brackets }} can only appear at the end of the attribute's value.
    # Furthermore unbalanced delimiters are not allowed.
    # Additionally section mustache delimiters, i.e., {{#, {{^, {{/ are
    # disallowed.
    disallowed_value_regex: "__amp_source_origin|"
        "(.|\\s){{|"    # Opening delimiter can only appear at the beginning.
        "}}(.|\\s)|"    # Closing delimiter can only appear at the end.
        "^{{.*[^}][^}]$|"    # Delimiters must be balanced.
        "^[^{][^{].*}}$|"    # Delimiters must be balanced.
        "^}}|"    # Also caught by the requirements on balanced delimiters.
        "{{$|"    # Also caught by the requirements on balanced delimiters.
        "{{#|"    # Section delimiters are disallowed.
        "{{/|"    # Section delimiters are disallowed.
        "{{\\^"  # Section delimiters are disallowed.
  }
}
# Same as above except that the attribute is not mandatory.
attr_lists: {
  name: "optional-src-amp4email"
  attrs: {
    name: "src"
    value_url: {
      protocol: "https"
      allow_relative: false
    }
    # Opening doubly curly brackets {{ (these are mustache delimiters) can only
    # appear at the beginning of the attribute's value. Likewise closing doubly
    # curly brackets }} can only appear at the end of the attribute's value.
    # Furthermore unbalanced delimiters are not allowed.
    # Additionally section mustache delimiters, i.e., {{#, {{^, {{/ are
    # disallowed.
    disallowed_value_regex: "__amp_source_origin|"
        "(.|\\s){{|"    # Opening delimiter can only appear at the beginning.
        "}}(.|\\s)|"    # Closing delimiter can only appear at the end.
        "^{{.*[^}][^}]$|"    # Delimiters must be balanced.
        "^[^{][^{].*}}$|"    # Delimiters must be balanced.
        "^}}|"    # Also caught by the requirements on balanced delimiters.
        "{{$|"    # Also caught by the requirements on balanced delimiters.
        "{{#|"    # Section delimiters are disallowed.
        "{{/|"    # Section delimiters are disallowed.
        "{{\\^"  # Section delimiters are disallowed.
  }
}

# Extended AMP globally optional tags.
attr_lists: {
  name: "extended-amp-global"
  attrs: {
    enabled_by: "transformed"
    name: "i-amphtml-layout"
    value_casei: "container"
    value_casei: "fill"
    value_casei: "fixed"
    value_casei: "fixed-height"
    value_casei: "flex-item"
    value_casei: "fluid"
    value_casei: "intrinsic"
    value_casei: "nodisplay"
    value_casei: "responsive"
  }
  attrs: { name: "media" }
  attrs: {
    name: "noloading"
    value: ""
  }
}
tags: {  # <amp-img>
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "AMP-IMG"
  # amp-img does not require a matching extension script, it's built in to v0.
  # js directly, so we explicitly list that dependency here.
  requires_condition: "amphtml javascript runtime (v0.js)"
  attrs: { name: "alt" }
  attrs: { name: "attribution" }
  attrs: { name: "crossorigin" }
  # https://developers.google.com/web/updates/2019/02/priority-hints
  attrs: {
    name: "importance"
    value_casei: "high"
    value_casei: "low"
    value_casei: "auto"
  }
  attrs: { name: "object-fit" }
  attrs: { name: "object-position" }
  attrs: { name: "placeholder" }
  attrs: { name: "referrerpolicy" }
  # <amp-bind>
  attrs: { name: "[alt]" }
  attrs: { name: "[attribution]" }
  attrs: { name: "[src]" }
  attrs: { name: "[srcset]" }
  attr_lists: "extended-amp-global"
  attr_lists: "lightboxable-elements"
  attr_lists: "mandatory-src-or-srcset"
  spec_url: "https://amp.dev/documentation/components/amp-img/"
  amp_layout: {
    supported_layouts: FILL
    supported_layouts: FIXED
    supported_layouts: FIXED_HEIGHT
    supported_layouts: FLEX_ITEM
    supported_layouts: INTRINSIC
    supported_layouts: NODISPLAY
    supported_layouts: RESPONSIVE
  }
}
# A duplicate of amp-img, but requires i-amphtml-ssr flag.
tags: {  # <amp-img i-amphtml-ssr>
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "AMP-IMG"
  spec_name: "amp-img (transformed)"
  # amp-img does not require a matching extension script, it's built in to v0.
  # js directly, so we explicitly list that dependency here.
  requires_condition: "amphtml javascript runtime (v0.js)"
  attrs: {
    dispatch_key: NAME_DISPATCH
    name: "i-amphtml-ssr"
    mandatory: true
  }
  attrs: { name: "alt" }
  attrs: { name: "attribution" }
  # https://developers.google.com/web/updates/2019/02/priority-hints
  attrs: {
    name: "importance"
    value_casei: "high"
    value_casei: "low"
    value_casei: "auto"
  }
  attrs: {
    name: "fetchpriority",
    value_casei: "high"
    value_casei: "low"
    value_casei: "auto"
  }
  attrs: { name: "object-fit" }
  attrs: { name: "object-position" }
  attrs: { name: "placeholder" }
  attrs: { name: "referrerpolicy" }
  # <amp-bind>
  attrs: { name: "[alt]" }
  attrs: { name: "[attribution]" }
  attrs: { name: "[src]" }
  attrs: { name: "[srcset]" }
  attr_lists: "extended-amp-global"
  attr_lists: "lightboxable-elements"
  attr_lists: "mandatory-src-or-srcset"
  spec_url: "https://amp.dev/documentation/components/amp-img/"
  amp_layout: {
    supported_layouts: FILL
    supported_layouts: FIXED
    supported_layouts: FIXED_HEIGHT
    supported_layouts: FLEX_ITEM
    supported_layouts: INTRINSIC
    supported_layouts: NODISPLAY
    supported_layouts: RESPONSIVE
  }
}
# See the restrictions on mandatory-src-amp4email, as well as the removal of
# `object-fit` and `object-position`.
tags: {  # <amp-img>
  html_format: AMP4EMAIL
  tag_name: "AMP-IMG"
  spec_name: "AMP-IMG (AMP4EMAIL)"
  # amp-img does not require a matching extension script, it's built in to v0.
  # js directly, so we explicitly list that dependency here. This is redundant
  # for email since v0.js is still required, but we include to for consistency
  # and to future proof.
  requires_condition: "amphtml javascript runtime (v0.js)"
  attrs: { name: "alt" }
  attrs: { name: "attribution" }
  attrs: { name: "placeholder" }
  attr_lists: "extended-amp-global"
  attr_lists: "mandatory-src-amp4email"
  # <amp-bind>
  attrs: { name: "[alt]" }
  attrs: { name: "[attribution]" }
  spec_url: "https://amp.dev/documentation/components/amp-img/"
  amp_layout: {
    supported_layouts: FILL
    supported_layouts: FIXED
    supported_layouts: FIXED_HEIGHT
    supported_layouts: FLEX_ITEM
    supported_layouts: INTRINSIC
    supported_layouts: NODISPLAY
    supported_layouts: RESPONSIVE
  }
}
tags: {  # <amp-layout>
  html_format: AMP
  html_format: AMP4ADS
  html_format: AMP4EMAIL
  tag_name: "AMP-LAYOUT"
  # amp-pixel does not require a matching extension script, it's built in to v0.
  # js directly, so we explicitly list that dependency here.
  requires_condition: "amphtml javascript runtime (v0.js)"
  attr_lists: "extended-amp-global"
  spec_url: "https://amp.dev/documentation/components/amp-layout/"
  amp_layout: {
    supported_layouts: FILL
    supported_layouts: FIXED
    supported_layouts: FIXED_HEIGHT
    supported_layouts: FLEX_ITEM
    supported_layouts: INTRINSIC
    supported_layouts: NODISPLAY
    supported_layouts: RESPONSIVE
    supported_layouts: CONTAINER
  }
}
tags: {  # <amp-pixel>
  html_format: AMP
  html_format: AMP4ADS
  tag_name: "AMP-PIXEL"
  # amp-pixel does not require a matching extension script, it's built in to v0.
  # js directly, so we explicitly list that dependency here.
  requires_condition: "amphtml javascript runtime (v0.js)"
  attrs: { name: "allow-ssr-img" }
  attrs: {
    name: "referrerpolicy"
    value: "no-referrer"
  }
  attrs: {
    name: "src"
    mandatory: true
    value_url: {
      protocol: "https"
      allow_relative: true  # Will be set to false at a future date.
      allow_empty: true
    }
    disallowed_value_regex: "__amp_source_origin"
  }
  attrs: {
    name: "attributionsrc"
    value_url: {
      protocol: "https"
      allow_empty: true
    }
  }
  attr_lists: "extended-amp-global"
  spec_url: "https://amp.dev/documentation/components/amp-pixel/"
  amp_layout {
    defines_default_height: true
    defines_default_width: true
    supported_layouts: FIXED
    supported_layouts: NODISPLAY
  }
}

# Transformed AMP specific tags.
tags: {
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "I-AMPHTML-SIZER"
  spec_name: "I-AMPHTML-SIZER-RESPONSIVE"
  explicit_attrs_only: true
  attrs: {
    name: "style"
    dispatch_key: NAME_DISPATCH
    mandatory: true
    disallowed_value_regex: "!\\s*important"
    css_declaration: {
      name: "display"
      value_casei: "block"
    }
    css_declaration: { name: "padding-top" }
  }
  attrs: {
    name: "i-amphtml-disable-ar"
    value: ""
  }
  attrs: {
    name: "slot"
    value: "i-amphtml-svc"
  }
}

tags: {
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "I-AMPHTML-SIZER"
  spec_name: "I-AMPHTML-SIZER-INTRINSIC"
  explicit_attrs_only: true
  attrs: {
    name: "class"
    value: "i-amphtml-sizer"
    mandatory: true
    dispatch_key: NAME_DISPATCH
  }
  attrs: {
    name: "i-amphtml-disable-ar"
    value: ""
  }
  attrs: {
    name: "slot"
    value: "i-amphtml-svc"
  }
}

tags: {
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "IMG"
  spec_name: "IMG-I-AMPHTML-INTRINSIC-SIZER"
  mandatory_parent: "I-AMPHTML-SIZER-INTRINSIC"
  attrs: {
    name: "alt"
    value: ""
    mandatory: true
  }
  attrs: {
    name: "aria-hidden"
    value: "true"
    mandatory: true
  }
  attrs: {
    name: "class"
    value: "i-amphtml-intrinsic-sizer"
    mandatory: true
  }
  attrs: {
    name: "role"
    value: "presentation"
    mandatory: true
  }
  attrs: {
    name: "src"
    value_regex: "data:image\\/svg\\+xml;charset=utf-8,\\s*<svg height=\"\\d+(\\.\\d+)?\" width=\"\\d+(\\.\\d+)?\" xmlns=\"http:\\/\\/www\\.w3\\.org\\/2000\\/svg\" version=\"1\\.1\"\\/>|data:image\\/svg\\+xml;charset=utf-8,\\s*<svg height='\\d+(\\.\\d+)?\' width='\\d+(\\.\\d+)?\' xmlns='http:\\/\\/www\\.w3\\.org\\/2000\\/svg' version='1\\.1'\\/>|data:image\\/svg\\+xml;base64,[a-zA-Z0-9+\\/=]+"
    mandatory: true
  }
}
tags: {
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "IMG"
  spec_name: "amp-img > img (transformed)"
  # Ideally we'd be able to use regular amp-img parent, but runtime currently
  # requires an i-amphtml-ssr attribute on the amp-img. We could do away with
  # that, though.
  mandatory_parent: "amp-img (transformed)"
  attrs: { name: "alt" }
  attrs: { name: "attribution" }
  attrs: { name: "height" }
  # https://developers.google.com/web/updates/2019/02/priority-hints
  attrs: {
    name: "fetchpriority"
    value_casei: "high"
    value_casei: "low"
    value_casei: "auto"
  }
  attrs: {
    name: "importance"
    value_casei: "high"
    value_casei: "low"
    value_casei: "auto"
  }
  attrs: { name: "object-fit" }
  attrs: { name: "object-position" }
  attrs: { name: "referrerpolicy" }
  attrs: { name: "sizes" }
  attrs: { name: "title" }
  attrs: { name: "width" }
  attr_lists: "mandatory-src-or-srcset"
  # SSR requires these explicit attributes
  attrs: {
    name: "class"
    value_regex: "i-amphtml-fill-content\\s+i-amphtml-replaced-content|"
        "i-amphtml-replaced-content\\s+i-amphtml-fill-content"
    mandatory: true
  }
  attrs: {
    name: "decoding"
    value: "async"
    mandatory: true
  }
  attrs: {
    name: "loading"
    value: "lazy"
    value: "eager"
  }
}
tags: {
  html_format: AMP
  enabled_by: "transformed"
  tag_name: "IMG"
  spec_name: "amp-img > img[placeholder] (transformed)"
  mandatory_parent: "amp-img (transformed)"
  attrs: { name: "alt" }
  attrs: { name: "attribution" }
  attrs: {
    name: "class"
    value: "i-amphtml-blurry-placeholder"
    mandatory: true
  }
  attrs: { name: "object-fit" }
  attrs: { name: "object-position" }
  attrs: {
    name: "placeholder"
    value: ""
    mandatory: true
    dispatch_key: NAME_DISPATCH
  }
  attrs: { name: "referrerpolicy" }
  attrs: { name: "sizes" }
  attrs: { name: "title" }
  attr_lists: "mandatory-src-or-srcset"
}

# AMP Layout attributes: implied for TagSpecs with amp_layout field
# set. Note that while these attributes are defined as optional here,
# depending on amp layout the validator will examine these fields and
# their values.
attr_lists: {
  name: "$AMP_LAYOUT_ATTRS"
  attrs: { name: "disable-inline-width" }
  attrs: { name: "height" }
  attrs: { name: "heights" }
  attrs: { name: "layout" }
  attrs: { name: "sizes" }
  attrs: { name: "width" }
  # <amp-bind>
  attrs: { name: "[height]" }
  attrs: { name: "[width]" }
}

# We generally want to allow publishers to use nonce on their own pages, to
# aid security on origin. The AMP Cache will strip these attributes so as
# not to break the behavior of the document on the cache. However, certain
# contexts do not make sense for nonce attributes. Email never is displayed
# on the publisher origin. Transformed documents are typically used as signed
# exchanges where the AMP Cache cannot strip the nonces. The nonce attribute
# is also present in the "common-extension-attrs" attr_lists below.
attr_lists: {
  name: "nonce-attr"
  attrs: {
    disabled_by: "amp4email"
    name: "nonce"
  }
}

# AMP Extension attributes.
attr_lists: {
  name: "common-extension-attrs"
  attrs: {
    name: "async"
    mandatory: true
    value: ""
  }
  attrs: {
    name: "crossorigin"
    value: "anonymous"
  }
  attrs: {
    disabled_by: "amp4email"
    name: "nonce"
  }
  attrs: {
    name: "type"
    value_casei: "text/javascript"
  }
}

# Mandatory "id" attribute.
attr_lists: {
  name: "mandatory-id-attr"
  attrs: {
    name: "id"
    mandatory: true
    # When updating this disallowed_value_regex, also update the entry for
    # "id" in $GLOBAL_ATTRS, and also validator-amp-script.protoascii and
    # validator-amp-mustache.protoascii.
    disallowed_value_regex: "(^|\\s)("  # Values are space separated
        "__amp_\\S*|"
        "__count__|"
        "__defineGetter__|"
        "__defineSetter__|"
        "__lookupGetter__|"
        "__lookupSetter__|"
        "__noSuchMethod__|"
        "__parent__|"
        "__proto__|"
        "__AMP_\\S*|"
        "\\$p|"
        "\\$proxy|"
        "acceptCharset|"
        "addEventListener|"
        "appendChild|"
        "assignedSlot|"
        "attachShadow|"
        "AMP|"
        "baseURI|"
        "checkValidity|"
        "childElementCount|"
        "childNodes|"
        "classList|"
        "className|"
        "clientHeight|"
        "clientLeft|"
        "clientTop|"
        "clientWidth|"
        "compareDocumentPosition|"
        "computedName|"
        "computedRole|"
        "contentEditable|"
        "createShadowRoot|"
        "enqueAction|"
        "firstChild|"
        "firstElementChild|"
        "getAnimations|"
        "getAttribute|"
        "getAttributeNS|"
        "getAttributeNode|"
        "getAttributeNodeNS|"
        "getBoundingClientRect|"
        "getClientRects|"
        "getDestinationInsertionPoints|"
        "getElementsByClassName|"
        "getElementsByTagName|"
        "getElementsByTagNameNS|"
        "getRootNode|"
        "hasAttribute|"
        "hasAttributeNS|"
        "hasAttributes|"
        "hasChildNodes|"
        "hasPointerCapture|"
        "i-amphtml-\\S*|"
        "innerHTML|"
        "innerText|"
        "inputMode|"
        "insertAdjacentElement|"
        "insertAdjacentHTML|"
        "insertAdjacentText|"
        "isContentEditable|"
        "isDefaultNamespace|"
        "isEqualNode|"
        "isSameNode|"
        "lastChild|"
        "lastElementChild|"
        "lookupNamespaceURI|"
        "namespaceURI|"
        "nextElementSibling|"
        "nextSibling|"
        "nodeName|"
        "nodeType|"
        "nodeValue|"
        "offsetHeight|"
        "offsetLeft|"
        "offsetParent|"
        "offsetTop|"
        "offsetWidth|"
        "outerHTML|"
        "outerText|"
        "ownerDocument|"
        "parentElement|"
        "parentNode|"
        "previousElementSibling|"
        "previousSibling|"
        "querySelector|"
        "querySelectorAll|"
        "releasePointerCapture|"
        "removeAttribute|"
        "removeAttributeNS|"
        "removeAttributeNode|"
        "removeChild|"
        "removeEventListener|"
        "replaceChild|"
        "reportValidity|"
        "requestPointerLock|"
        "scrollHeight|"
        "scrollIntoView|"
        "scrollIntoViewIfNeeded|"
        "scrollLeft|"
        "scrollWidth|"
        "setAttribute|"
        "setAttributeNS|"
        "setAttributeNode|"
        "setAttributeNodeNS|"
        "setPointerCapture|"
        "shadowRoot|"
        "styleMap|"
        "tabIndex|"
        "tagName|"
        "textContent|"
        "toString|"
        "valueOf|"
        "(webkit|ms|moz|o)dropzone|"
        "(webkit|moz|ms|o)MatchesSelector|"
        "(webkit|moz|ms|o)RequestFullScreen|"
        "(webkit|moz|ms|o)RequestFullscreen"
        ")(\\s|$)"
  }
}


# Disallows document properties on "name" attribute for use on <form>.
attr_lists: {
  name: "form-name-attr"
  attrs: {
    name: "name"
    disallowed_value_regex: "(^|\\s)("
        "ATTRIBUTE_NODE|"
        "CDATA_SECTION_NODE|"
        "COMMENT_NODE|"
        "DOCUMENT_FRAGMENT_NODE|"
        "DOCUMENT_NODE|"
        "DOCUMENT_POSITION_CONTAINED_BY|"
        "DOCUMENT_POSITION_CONTAINS|"
        "DOCUMENT_POSITION_DISCONNECTED|"
        "DOCUMENT_POSITION_FOLLOWING|"
        "DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC|"
        "DOCUMENT_POSITION_PRECEDING|"
        "DOCUMENT_TYPE_NODE|"
        "ELEMENT_NODE|"
        "ENTITY_NODE|"
        "ENTITY_REFERENCE_NODE|"
        "NOTATION_NODE|"
        "PROCESSING_INSTRUCTION_NODE|"
        "TEXT_NODE|"
        "URL|"
        "URLUnencoded|"
        "__amp_\\S*|"
        "__count__|"
        "__defineGetter__|"
        "__defineSetter__|"
        "__lookupGetter__|"
        "__lookupSetter__|"
        "__noSuchMethod__|"
        "__parent__|"
        "__proto__|"
        "__AMP_\\S*|"
        "activeElement|"
        "addEventListener|"
        "adoptNode|"
        "alinkColor|"
        "all|"
        "anchors|"
        "append|"
        "appendChild|"
        "applets|"
        "baseURI|"
        "bgColor|"
        "body|"
        "captureEvents|"
        "caretPositionFromPoint|"
        "caretRangeFromPoint|"
        "characterSet|"
        "charset|"
        "childElementCount|"
        "childNodes|"
        "children|"
        "clear|"
        "cloneNode|"
        "close|"
        "compareDocumentPosition|"
        "compatMode|"
        "constructor|"
        "contains|"
        "contentType|"
        "cookie|"
        "createAttribute|"
        "createAttributeNS|"
        "createCDATASection|"
        "createComment|"
        "createDocumentFragment|"
        "createElement|"
        "createElementNS|"
        "createEvent|"
        "createExpression|"
        "createNSResolver|"
        "createNodeIterator|"
        "createProcessingInstruction|"
        "createRange|"
        "createTextNode|"
        "createTreeWalker|"
        "currentScript|"
        "defaultView|"
        "designMode|"
        "dir|"
        "dispatchEvent|"
        "doctype|"
        "documentElement|"
        "documentURI|"
        "domain|"
        "elementFromPoint|"
        "elementsFromPoint|"
        "embeds|"
        "enableStyleSheetsForSet|"
        "evaluate|"
        "execCommand|"
        "execCommandShowHelp|"
        "exitFullscreen|"
        "exitPictureInPicture|"
        "exitPointerLock|"
        "fgColor|"
        "firstChild|"
        "firstElementChild|"
        "focus|"
        "fonts|"
        "forms|"
        "fullscreen|"
        "fullscreenElement|"
        "fullscreenEnabled|"
        "getCSSCanvasContext|"
        "getElementById|"
        "getElementsByClassName|"
        "getElementsByName|"
        "getElementsByTagName|"
        "getElementsByTagNameNS|"
        "getOverrideStyle|"
        "getRootNode|"
        "getSelection|"
        "hasChildNodes|"
        "hasFocus|"
        "hasOwnProperty|"
        "hasStorageAccess|"
        "head|"
        "hidden|"
        "images|"
        "implementation|"
        "importNode|"
        "inputEncoding|"
        "insertBefore|"
        "isConnected|"
        "isDefaultNamespace|"
        "isEqualNode|"
        "isPrototypeOf|"
        "isSameNode|"
        "l10n|"
        "lastChild|"
        "lastElementChild|"
        "lastModified|"
        "lastStyleSheetSet|"
        "linkColor|"
        "links|"
        "location|"
        "lookupNamespaceURI|"
        "lookupPrefix|"
        "mozCancelFullScreen|"
        "mozFullScreen|"
        "mozFullScreenElement|"
        "mozFullScreenEnabled|"
        "mozSetImageElement|"
        "msCSSOMElementFloatMetrics|"
        "msCapsLockWarningOff|"
        "msElementsFromPoint|"
        "msElementsFromRect|"
        "nextSibling|"
        "nodeName|"
        "nodeType|"
        "nodeValue|"
        "normalize|"
        "onabort|"
        "onactivate|"
        "onafterscriptexecute|"
        "onanimationcancel|"
        "onanimationend|"
        "onanimationiteration|"
        "onanimationstart|"
        "onauxclick|"
        "onbeforeactivate|"
        "onbeforecopy|"
        "onbeforecut|"
        "onbeforedeactivate|"
        "onbeforeinput|"
        "onbeforepaste|"
        "onbeforescriptexecute|"
        "onblur|"
        "oncancel|"
        "oncanplay|"
        "oncanplaythrough|"
        "onchange|"
        "onclick|"
        "onclose|"
        "oncontextmenu|"
        "oncopy|"
        "oncuechange|"
        "oncut|"
        "ondblclick|"
        "ondeactivate|"
        "ondrag|"
        "ondragend|"
        "ondragenter|"
        "ondragexit|"
        "ondragleave|"
        "ondragover|"
        "ondragstart|"
        "ondrop|"
        "ondurationchange|"
        "onemptied|"
        "onended|"
        "onerror|"
        "onfocus|"
        "onfreeze|"
        "onfullscreenchange|"
        "onfullscreenerror|"
        "ongotpointercapture|"
        "oninput|"
        "oninvalid|"
        "onkeydown|"
        "onkeypress|"
        "onkeyup|"
        "onload|"
        "onloadeddata|"
        "onloadedmetadata|"
        "onloadend|"
        "onloadstart|"
        "onlostpointercapture|"
        "onmousedown|"
        "onmouseenter|"
        "onmouseleave|"
        "onmousemove|"
        "onmouseout|"
        "onmouseover|"
        "onmouseup|"
        "onmousewheel|"
        "onmozfullscreenchange|"
        "onmozfullscreenerror|"
        "onmscontentzoom|"
        "onmsgesturechange|"
        "onmsgesturedoubletap|"
        "onmsgestureend|"
        "onmsgesturehold|"
        "onmsgesturestart|"
        "onmsgesturetap|"
        "onmsinertiastart|"
        "onmsmanipulationstatechanged|"
        "onmssitemodejumplistitemremoved|"
        "onmsthumbnailclick|"
        "onpaste|"
        "onpause|"
        "onplay|"
        "onplaying|"
        "onpointercancel|"
        "onpointerdown|"
        "onpointerenter|"
        "onpointerleave|"
        "onpointerlockchange|"
        "onpointerlockerror|"
        "onpointermove|"
        "onpointerout|"
        "onpointerover|"
        "onpointerup|"
        "onprogress|"
        "onratechange|"
        "onreadystatechange|"
        "onrejectionhandled|"
        "onreset|"
        "onresize|"
        "onresume|"
        "onscroll|"
        "onsearch|"
        "onseeked|"
        "onseeking|"
        "onselect|"
        "onselectionchange|"
        "onselectstart|"
        "onshow|"
        "onstalled|"
        "onstop|"
        "onsubmit|"
        "onsuspend|"
        "ontimeupdate|"
        "ontoggle|"
        "ontransitioncancel|"
        "ontransitionend|"
        "ontransitionrun|"
        "ontransitionstart|"
        "onunhandledrejection|"
        "onvisibilitychange|"
        "onvolumechange|"
        "onwaiting|"
        "onwebkitanimationend|"
        "onwebkitanimationiteration|"
        "onwebkitanimationstart|"
        "onwebkitfullscreenchange|"
        "onwebkitfullscreenerror|"
        "onwebkitmouseforcechanged|"
        "onwebkitmouseforcedown|"
        "onwebkitmouseforceup|"
        "onwebkitmouseforcewillbegin|"
        "onwebkittransitionend|"
        "onwheel|"
        "open|"
        "origin|"
        "ownerDocument|"
        "parentElement|"
        "parentNode|"
        "pictureInPictureElement|"
        "pictureInPictureEnabled|"
        "plugins|"
        "pointerLockElement|"
        "preferredStyleSheetSet|"
        "prepend|"
        "previousSibling|"
        "propertyIsEnumerable|"
        "queryCommandEnabled|"
        "queryCommandIndeterm|"
        "queryCommandState|"
        "queryCommandSupported|"
        "queryCommandText|"
        "queryCommandValue|"
        "querySelector|"
        "querySelectorAll|"
        "readyState|"
        "referrer|"
        "registerElement|"
        "releaseCapture|"
        "releaseEvents|"
        "removeChild|"
        "removeEventListener|"
        "replaceChild|"
        "requestStorageAccess|"
        "rootElement|"
        "scripts|"
        "scrollingElement|"
        "selectedStyleSheetSet|"
        "styleSheetSets|"
        "styleSheets|"
        "textContent|"
        "title|"
        "toLocaleString|"
        "toSource|"
        "toString|"
        "updateSettings|"
        "valueOf|"
        "visibilityState|"
        "vlinkColor|"
        "wasDiscarded|"
        "webkitCancelFullScreen|"
        "webkitCurrentFullScreenElement|"
        "webkitExitFullscreen|"
        "webkitFullScreenKeyboardInputAllowed|"
        "webkitFullscreenElement|"
        "webkitFullscreenEnabled|"
        "webkitHidden|"
        "webkitIsFullScreen|"
        "webkitVisibilityState|"
        "write|"
        "writeln|"
        "xmlEncoding|"
        "xmlStandalone|"
        "xmlVersion"
        ")(\\s|$)"
  }
}

# Not mandatory "name" attribute.
attr_lists: {
  name: "name-attr"
  attrs: {
    name: "name"
    # When updating this disallowed_value_regex, also update for
    # mandatory-name-attr.
    disallowed_value_regex: "(^|\\s)("  # Values are space separated
        "__amp_\\S*|"
        "__count__|"
        "__defineGetter__|"
        "__defineSetter__|"
        "__lookupGetter__|"
        "__lookupSetter__|"
        "__noSuchMethod__|"
        "__parent__|"
        "__proto__|"
        "__AMP_\\S*|"
        "\\$p|"
        "\\$proxy|"
        "acceptCharset|"
        "addEventListener|"
        "appendChild|"
        "assignedSlot|"
        "attachShadow|"
        "baseURI|"
        "checkValidity|"
        "childElementCount|"
        "childNodes|"
        "classList|"
        "className|"
        "clientHeight|"
        "clientLeft|"
        "clientTop|"
        "clientWidth|"
        "compareDocumentPosition|"
        "computedName|"
        "computedRole|"
        "contentEditable|"
        "createShadowRoot|"
        "enqueAction|"
        "firstChild|"
        "firstElementChild|"
        "getAnimations|"
        "getAttribute|"
        "getAttributeNS|"
        "getAttributeNode|"
        "getAttributeNodeNS|"
        "getBoundingClientRect|"
        "getClientRects|"
        "getDestinationInsertionPoints|"
        "getElementsByClassName|"
        "getElementsByTagName|"
        "getElementsByTagNameNS|"
        "getRootNode|"
        "hasAttribute|"
        "hasAttributeNS|"
        "hasAttributes|"
        "hasChildNodes|"
        "hasPointerCapture|"
        "innerHTML|"
        "innerText|"
        "inputMode|"
        "insertAdjacentElement|"
        "insertAdjacentHTML|"
        "insertAdjacentText|"
        "isContentEditable|"
        "isDefaultNamespace|"
        "isEqualNode|"
        "isSameNode|"
        "lastChild|"
        "lastElementChild|"
        "lookupNamespaceURI|"
        "namespaceURI|"
        "nextElementSibling|"
        "nextSibling|"
        "nodeName|"
        "nodeType|"
        "nodeValue|"
        "offsetHeight|"
        "offsetLeft|"
        "offsetParent|"
        "offsetTop|"
        "offsetWidth|"
        "outerHTML|"
        "outerText|"
        "ownerDocument|"
        "parentElement|"
        "parentNode|"
        "previousElementSibling|"
        "previousSibling|"
        "querySelector|"
        "querySelectorAll|"
        "releasePointerCapture|"
        "removeAttribute|"
        "removeAttributeNS|"
        "removeAttributeNode|"
        "removeChild|"
        "removeEventListener|"
        "replaceChild|"
        "reportValidity|"
        "requestPointerLock|"
        "scrollHeight|"
        "scrollIntoView|"
        "scrollIntoViewIfNeeded|"
        "scrollLeft|"
        "scrollWidth|"
        "setAttribute|"
        "setAttributeNS|"
        "setAttributeNode|"
        "setAttributeNodeNS|"
        "setPointerCapture|"
        "shadowRoot|"
        "styleMap|"
        "tabIndex|"
        "tagName|"
        "textContent|"
        "toString|"
        "valueOf|"
        "(webkit|ms|moz|o)dropzone|"
        "(webkit|moz|ms|o)MatchesSelector|"
        "(webkit|moz|ms|o)RequestFullScreen|"
        "(webkit|moz|ms|o)RequestFullscreen"
        ")(\\s|$)"
  }
}

# Mandatory "name" attribute.
attr_lists: {
  name: "mandatory-name-attr"
  attrs: {
    name: "name"
    mandatory: true
    # When updating this disallowed_value_regex, also update for name-attr.
    disallowed_value_regex: "(^|\\s)("  # Values are space separated
        "__amp_\\S*|"
        "__count__|"
        "__defineGetter__|"
        "__defineSetter__|"
        "__lookupGetter__|"
        "__lookupSetter__|"
        "__noSuchMethod__|"
        "__parent__|"
        "__proto__|"
        "__AMP_\\S*|"
        "\\$p|"
        "\\$proxy|"
        "acceptCharset|"
        "addEventListener|"
        "appendChild|"
        "assignedSlot|"
        "attachShadow|"
        "baseURI|"
        "checkValidity|"
        "childElementCount|"
        "childNodes|"
        "classList|"
        "className|"
        "clientHeight|"
        "clientLeft|"
        "clientTop|"
        "clientWidth|"
        "compareDocumentPosition|"
        "computedName|"
        "computedRole|"
        "contentEditable|"
        "createShadowRoot|"
        "enqueAction|"
        "firstChild|"
        "firstElementChild|"
        "getAnimations|"
        "getAttribute|"
        "getAttributeNS|"
        "getAttributeNode|"
        "getAttributeNodeNS|"
        "getBoundingClientRect|"
        "getClientRects|"
        "getDestinationInsertionPoints|"
        "getElementsByClassName|"
        "getElementsByTagName|"
        "getElementsByTagNameNS|"
        "getRootNode|"
        "hasAttribute|"
        "hasAttributeNS|"
        "hasAttributes|"
        "hasChildNodes|"
        "hasPointerCapture|"
        "innerHTML|"
        "innerText|"
        "inputMode|"
        "insertAdjacentElement|"
        "insertAdjacentHTML|"
        "insertAdjacentText|"
        "isContentEditable|"
        "isDefaultNamespace|"
        "isEqualNode|"
        "isSameNode|"
        "lastChild|"
        "lastElementChild|"
        "lookupNamespaceURI|"
        "namespaceURI|"
        "nextElementSibling|"
        "nextSibling|"
        "nodeName|"
        "nodeType|"
        "nodeValue|"
        "offsetHeight|"
        "offsetLeft|"
        "offsetParent|"
        "offsetTop|"
        "offsetWidth|"
        "outerHTML|"
        "outerText|"
        "ownerDocument|"
        "parentElement|"
        "parentNode|"
        "previousElementSibling|"
        "previousSibling|"
        "querySelector|"
        "querySelectorAll|"
        "releasePointerCapture|"
        "removeAttribute|"
        "removeAttributeNS|"
        "removeAttributeNode|"
        "removeChild|"
        "removeEventListener|"
        "replaceChild|"
        "reportValidity|"
        "requestPointerLock|"
        "scrollHeight|"
        "scrollIntoView|"
        "scrollIntoViewIfNeeded|"
        "scrollLeft|"
        "scrollWidth|"
        "setAttribute|"
        "setAttributeNS|"
        "setAttributeNode|"
        "setAttributeNodeNS|"
        "setPointerCapture|"
        "shadowRoot|"
        "styleMap|"
        "tabIndex|"
        "tagName|"
        "textContent|"
        "toString|"
        "valueOf|"
        "(webkit|ms|moz|o)dropzone|"
        "(webkit|moz|ms|o)MatchesSelector|"
        "(webkit|moz|ms|o)RequestFullScreen|"
        "(webkit|moz|ms|o)RequestFullscreen"
        ")(\\s|$)"
  }
}

# Global attributes: These can be used in all tags.
attr_lists: {
  name: "$GLOBAL_ATTRS"
  # For schema.org annotations.
  attrs: { name: "itemid" }
  attrs: { name: "itemprop" }
  attrs: { name: "itemref" }
  attrs: { name: "itemscope" }
  attrs: { name: "itemtype" }
  # Also for schema.org, RDFa syntax
  attrs: { name: "about" }
  attrs: { name: "content" }
  attrs: { name: "datatype" }
  attrs: { name: "inlist" }
  attrs: { name: "prefix" }
  attrs: { name: "property" }
  attrs: {
    name: "rel"
    disallowed_value_regex: "(^|\\s)("  # Values are space separated
        "canonical|"
        "components|"
        "dns-prefetch|"
        "import|"
        "manifest|"
        "preconnect|"
        "preload|"
        "prerender|"
        "serviceworker|"
        "stylesheet|"
        "subresource"
        ")(\\s|$)"
  }
  attrs: { name: "resource" }
  attrs: { name: "rev" }
  attrs: {
    name: "style"
    # `style` attribute value validated against Document Level CSS rules defined
    # in validator-css.protoascii.
    value_doc_css: true
  }
  attrs: { name: "typeof" }
  attrs: { name: "vocab" }
  # 3.2.5 HTML5 Global attributes.
  attrs: { name: "accesskey" }
  attrs: {
    name: "class"
    # attribute "class" is handled within the Validator engine, since we need to
    # handle transformed and non-transformed cases while still allowing "class"
    # attribute generically.
    # disallowed_value_regex: "(^|[\t\n\f\r ])i-amphtml-"
  }
  attrs: { name: "dir" }
  attrs: { name: "draggable" }
  attrs: {
    name: "hidden"
    value: ""
  }
  attrs: {
    name: "id"
    # When updating this disallowed_value_regex, also update for
    # mandatory-id-attr, validator-amp-script.protoascii, and
    # validator-amp-mustache.protoascii.
    disallowed_value_regex: "(^|\\s)("  # Values are space separated
        "__amp_\\S*|"
        "__count__|"
        "__defineGetter__|"
        "__defineSetter__|"
        "__lookupGetter__|"
        "__lookupSetter__|"
        "__noSuchMethod__|"
        "__parent__|"
        "__proto__|"
        "__AMP_\\S*|"
        "\\$p|"
        "\\$proxy|"
        "acceptCharset|"
        "addEventListener|"
        "appendChild|"
        "assignedSlot|"
        "attachShadow|"
        "AMP|"
        "baseURI|"
        "checkValidity|"
        "childElementCount|"
        "childNodes|"
        "classList|"
        "className|"
        "clientHeight|"
        "clientLeft|"
        "clientTop|"
        "clientWidth|"
        "compareDocumentPosition|"
        "computedName|"
        "computedRole|"
        "contentEditable|"
        "createShadowRoot|"
        "enqueAction|"
        "firstChild|"
        "firstElementChild|"
        "getAnimations|"
        "getAttribute|"
        "getAttributeNS|"
        "getAttributeNode|"
        "getAttributeNodeNS|"
        "getBoundingClientRect|"
        "getClientRects|"
        "getDestinationInsertionPoints|"
        "getElementsByClassName|"
        "getElementsByTagName|"
        "getElementsByTagNameNS|"
        "getRootNode|"
        "hasAttribute|"
        "hasAttributeNS|"
        "hasAttributes|"
        "hasChildNodes|"
        "hasPointerCapture|"
        "i-amphtml-\\S*|"
        "innerHTML|"
        "innerText|"
        "inputMode|"
        "insertAdjacentElement|"
        "insertAdjacentHTML|"
        "insertAdjacentText|"
        "isContentEditable|"
        "isDefaultNamespace|"
        "isEqualNode|"
        "isSameNode|"
        "lastChild|"
        "lastElementChild|"
        "lookupNamespaceURI|"
        "namespaceURI|"
        "nextElementSibling|"
        "nextSibling|"
        "nodeName|"
        "nodeType|"
        "nodeValue|"
        "offsetHeight|"
        "offsetLeft|"
        "offsetParent|"
        "offsetTop|"
        "offsetWidth|"
        "outerHTML|"
        "outerText|"
        "ownerDocument|"
        "parentElement|"
        "parentNode|"
        "previousElementSibling|"
        "previousSibling|"
        "querySelector|"
        "querySelectorAll|"
        "releasePointerCapture|"
        "removeAttribute|"
        "removeAttributeNS|"
        "removeAttributeNode|"
        "removeChild|"
        "removeEventListener|"
        "replaceChild|"
        "reportValidity|"
        "requestPointerLock|"
        "scrollHeight|"
        "scrollIntoView|"
        "scrollIntoViewIfNeeded|"
        "scrollLeft|"
        "scrollWidth|"
        "setAttribute|"
        "setAttributeNS|"
        "setAttributeNode|"
        "setAttributeNodeNS|"
        "setPointerCapture|"
        "shadowRoot|"
        "styleMap|"
        "tabIndex|"
        "tagName|"
        "textContent|"
        "toString|"
        "valueOf|"
        "(webkit|ms|moz|o)dropzone|"
        "(webkit|moz|ms|o)MatchesSelector|"
        "(webkit|moz|ms|o)RequestFullScreen|"
        "(webkit|moz|ms|o)RequestFullscreen"
        ")(\\s|$)"
  }
  attrs: { name: "lang" }
  attrs: { name: "slot" }
  attrs: { name: "tabindex" }
  attrs: { name: "title" }
  attrs: { name: "translate" }
  # Accessible Rich Internet Applications http://www.w3.org/TR/wai-aria/
  attrs: { name: "aria-activedescendant" }
  attrs: { name: "aria-atomic" }
  attrs: { name: "aria-autocomplete" }
  attrs: { name: "aria-busy" }
  attrs: { name: "aria-checked" }
  attrs: { name: "aria-controls" }
  attrs: { name: "aria-current" }
  attrs: { name: "aria-describedby" }
  attrs: { name: "aria-disabled" }
  attrs: { name: "aria-dropeffect" }
  attrs: { name: "aria-expanded" }
  attrs: { name: "aria-flowto" }
  attrs: { name: "aria-grabbed" }
  attrs: { name: "aria-haspopup" }
  attrs: { name: "aria-hidden" }
  attrs: { name: "aria-invalid" }
  attrs: { name: "aria-label" }
  attrs: { name: "aria-labelledby" }
  attrs: { name: "aria-level" }
  attrs: { name: "aria-live" }
  attrs: { name: "aria-modal" }
  attrs: { name: "aria-multiline" }
  attrs: { name: "aria-multiselectable" }
  attrs: { name: "aria-orientation" }
  attrs: { name: "aria-owns" }
  attrs: { name: "aria-posinset" }
  attrs: { name: "aria-pressed" }
  attrs: { name: "aria-readonly" }
  attrs: { name: "aria-relevant" }
  attrs: { name: "aria-required" }
  attrs: { name: "aria-selected" }
  attrs: { name: "aria-setsize" }
  attrs: { name: "aria-sort" }
  attrs: { name: "aria-valuemax" }
  attrs: { name: "aria-valuemin" }
  attrs: { name: "aria-valuenow" }
  attrs: { name: "aria-valuetext" }
  attrs: {
    name: "on"
    trigger: {
      if_value_regex: "tap:.*"
      also_requires_attr: "role"
      also_requires_attr: "tabindex"
    }
  }
  attrs: { name: "role" }
  # For placeholders inside amp-ad and other tags, we allow the
  # placeholder empty attribute. See e.g.
  # https://github.com/ampproject/amphtml/pull/284/commits
  attrs: { name: "placeholder" value: "" }
  # We allow the empty fallback attribute on any element
  attrs: { name: "fallback" value: "" }
  attrs: { name: "overflow" }
  # amp-access specific attributes, see
  # https://amp.dev/documentation/components/amp-access
  # TODO(gregable): These should only be allowed on any tag inside BODY or HEAD.
  attrs: { name: "amp-access" }
  attrs: { name: "amp-access-behavior" }
  attrs: { name: "amp-access-hide" }
  attrs: { name: "amp-access-id" }
  attrs: { name: "amp-access-loader" }
  attrs: { name: "amp-access-loading" }
  attrs: { name: "amp-access-off" }
  attrs: { name: "amp-access-on" }
  attrs: { name: "amp-access-show" }
  attrs: { name: "amp-access-style" }
  attrs: { name: "amp-access-template" }
  attrs: { name: "i-amp-access-id" }
  # amp-form specific attributes, see
  # https://github.com/ampproject/amphtml/issues/5268
  attrs: {
    name: "validation-for"
    trigger: {
      also_requires_attr: "visible-when-invalid"
    }
  }
  attrs: {
    name: "visible-when-invalid"
    value: "badInput"
    value: "customError"
    value: "patternMismatch"
    value: "rangeOverflow"
    value: "rangeUnderflow"
    value: "stepMismatch"
    value: "tooLong"
    value: "tooShort"
    value: "typeMismatch"
    value: "valueMissing"
    trigger: {
      also_requires_attr: "validation-for"
    }
  }
  # amp-fx-collection specific attributes, see
  # https://amp.dev/documentation/components/amp-fx-collection
  attrs: {
    name: "amp-fx"
    value_regex_casei: "(fade-in|"
                        "fade-in-scroll|"
                        "float-in-bottom|"
                        "float-in-top|"
                        "fly-in-bottom|"
                        "fly-in-left|"
                        "fly-in-right|"
                        "fly-in-top|"
                        "parallax)"
                       "(\\s|"
                        "fade-in|"
                        "fade-in-scroll|"
                        "float-in-bottom|"
                        "float-in-top|"
                        "fly-in-bottom|"
                        "fly-in-left|"
                        "fly-in-right|"
                        "fly-in-top|"
                        "parallax)*"
    requires_extension: "amp-fx-collection"
  }
  # amp-subscriptions specific attributes, see
  # https://amp.dev/documentation/components/amp-subscriptions
  attrs: {
    name: "subscriptions-action"
    requires_extension: "amp-subscriptions"
  }
  attrs: {
    name: "subscriptions-actions"
    value: ""
    requires_extension: "amp-subscriptions"
  }
  attrs: {
    name: "subscriptions-decorate"
    requires_extension: "amp-subscriptions"
  }
  attrs: {
    name: "subscriptions-dialog"
    value: ""
    requires_extension: "amp-subscriptions"
  }
  attrs: {
    name: "subscriptions-display"
    requires_extension: "amp-subscriptions"
  }
  attrs: {
    name: "subscriptions-lang"
    requires_extension: "amp-subscriptions"
  }
  attrs: {
    name: "subscriptions-section"
    value_casei: "actions"
    value_casei: "content"
    value_casei: "content-not-granted"
    value_casei: "loading"
    requires_extension: "amp-subscriptions"
  }
  attrs: {
    name: "subscriptions-service"
    requires_extension: "amp-subscriptions"
  }
  # amp-subscriptions-google specific attributes, see
  # https://amp.dev/documentation/components/amp-subscriptions-google
  attrs: {
    name: "subscriptions-google-rtc"
    requires_extension: "amp-subscriptions-google"
  }
  # amp-next-page specific attributes, see
  # https://amp.dev/documentation/components/amp-next-page
  attrs: {
    name: "next-page-hide"
    requires_extension: "amp-next-page"
  }
  attrs: {
    name: "next-page-replace"
    requires_extension: "amp-next-page"
  }
  # <amp-bind>
  attrs: { name: "[aria-activedescendant]" }
  attrs: { name: "[aria-atomic]" }
  attrs: { name: "[aria-autocomplete]" }
  attrs: { name: "[aria-busy]" }
  attrs: { name: "[aria-checked]" }
  attrs: { name: "[aria-controls]" }
  attrs: { name: "[aria-describedby]" }
  attrs: { name: "[aria-disabled]" }
  attrs: { name: "[aria-dropeffect]" }
  attrs: { name: "[aria-expanded]" }
  attrs: { name: "[aria-flowto]" }
  attrs: { name: "[aria-grabbed]" }
  attrs: { name: "[aria-haspopup]" }
  attrs: { name: "[aria-hidden]" }
  attrs: { name: "[aria-invalid]" }
  attrs: { name: "[aria-label]" }
  attrs: { name: "[aria-labelledby]" }
  attrs: { name: "[aria-level]" }
  attrs: { name: "[aria-live]" }
  attrs: { name: "[aria-multiline]" }
  attrs: { name: "[aria-multiselectable]" }
  attrs: { name: "[aria-orientation]" }
  attrs: { name: "[aria-owns]" }
  attrs: { name: "[aria-posinset]" }
  attrs: { name: "[aria-pressed]" }
  attrs: { name: "[aria-readonly]" }
  attrs: { name: "[aria-relevant]" }
  attrs: { name: "[aria-required]" }
  attrs: { name: "[aria-selected]" }
  attrs: { name: "[aria-setsize]" }
  attrs: { name: "[aria-sort]" }
  attrs: { name: "[aria-valuemax]" }
  attrs: { name: "[aria-valuemin]" }
  attrs: { name: "[aria-valuenow]" }
  attrs: { name: "[aria-valuetext]" }
  attrs: { name: "[class]" }
  attrs: { name: "[hidden]" }
  attrs: { name: "[text]" }
  attrs: {
    enabled_by: "transformed"
    name: "i-amphtml-binding"
    value: ""
  }
  # <amp-sidebar>
  attrs: {
    name: "autoscroll"
    requires_ancestor {
      marker: AUTOSCROLL
    }
  }
}

# Error Specificity: Used in the verbose validator to select between multiple
# generated error types for a failing error. A higher number means that the
# error is more specific, ie: more helpful, preferred.
error_specificity { code: UNKNOWN_CODE specificity: 0 }
error_specificity { code: MANDATORY_CDATA_MISSING_OR_INCORRECT specificity: 1 }
error_specificity { code: CDATA_VIOLATES_DENYLIST specificity: 2 }
error_specificity { code: NON_WHITESPACE_CDATA_ENCOUNTERED specificity: 3 }
error_specificity { code: INVALID_JSON_CDATA specificity: 4 }
error_specificity { code: DISALLOWED_TAG_ANCESTOR specificity: 5 }
error_specificity { code: MANDATORY_TAG_ANCESTOR specificity: 6 }
error_specificity { code: MANDATORY_TAG_ANCESTOR_WITH_HINT specificity: 7 }
error_specificity { code: MANDATORY_TAG_MISSING specificity: 8 }
error_specificity { code: WRONG_PARENT_TAG specificity: 9 }
error_specificity { code: TAG_REQUIRED_BY_MISSING specificity: 10 }
error_specificity { code: TAG_EXCLUDED_BY_TAG specificity: 11 }
error_specificity { code: MISSING_REQUIRED_EXTENSION specificity: 12 }
error_specificity { code: ATTR_MISSING_REQUIRED_EXTENSION specificity: 13 }
error_specificity { code: WARNING_TAG_REQUIRED_BY_MISSING specificity: 14 }
error_specificity { code: EXTENSION_UNUSED specificity: 15 }
error_specificity { code: WARNING_EXTENSION_UNUSED specificity: 16 }
error_specificity { code: WARNING_EXTENSION_DEPRECATED_VERSION specificity: 17 }
error_specificity { code: INVALID_EXTENSION_VERSION specificity: 18 }
error_specificity { code: INVALID_EXTENSION_PATH specificity: 19 }
error_specificity { code: NON_LTS_SCRIPT_AFTER_LTS specificity: 20 }
error_specificity { code: LTS_SCRIPT_AFTER_NON_LTS specificity: 21 }
error_specificity { code: INCORRECT_SCRIPT_RELEASE_VERSION specificity: 22 }
error_specificity { code: DISALLOWED_AMP_DOMAIN specificity: 23 }
error_specificity { code: DISALLOWED_TAG specificity: 24 }
error_specificity { code: DISALLOWED_ATTR specificity: 25 }
error_specificity { code: INVALID_ATTR_VALUE specificity: 26 }
error_specificity { code: DUPLICATE_ATTRIBUTE specificity: 27 }
error_specificity { code: ATTR_VALUE_REQUIRED_BY_LAYOUT specificity: 28 }
error_specificity { code: MANDATORY_ATTR_MISSING specificity: 29 }
error_specificity { code: MANDATORY_ONEOF_ATTR_MISSING specificity: 30 }
error_specificity { code: MANDATORY_ANYOF_ATTR_MISSING specificity: 31 }
error_specificity { code: ATTR_REQUIRED_BUT_MISSING specificity: 32 }
error_specificity { code: DUPLICATE_UNIQUE_TAG specificity: 33 }
error_specificity { code: DUPLICATE_UNIQUE_TAG_WARNING specificity: 34 }
error_specificity { code: STYLESHEET_TOO_LONG specificity: 35 }
error_specificity { code: STYLESHEET_AND_INLINE_STYLE_TOO_LONG specificity: 36 }
error_specificity { code: INLINE_STYLE_TOO_LONG specificity: 37 }
error_specificity { code: INLINE_SCRIPT_TOO_LONG specificity: 38 }
error_specificity { code: CSS_SYNTAX_INVALID_AT_RULE specificity: 39 }
error_specificity {
  code: MANDATORY_PROPERTY_MISSING_FROM_ATTR_VALUE specificity: 40
}
error_specificity { code: INVALID_PROPERTY_VALUE_IN_ATTR_VALUE specificity: 41 }
error_specificity { code: DISALLOWED_PROPERTY_IN_ATTR_VALUE specificity: 42 }
error_specificity { code: MUTUALLY_EXCLUSIVE_ATTRS specificity: 43 }
error_specificity { code: UNESCAPED_TEMPLATE_IN_ATTR_VALUE specificity: 44 }
error_specificity { code: TEMPLATE_PARTIAL_IN_ATTR_VALUE specificity: 45 }
error_specificity { code: TEMPLATE_IN_ATTR_NAME specificity: 46 }
error_specificity {
  code: INCONSISTENT_UNITS_FOR_WIDTH_AND_HEIGHT specificity: 47
}
error_specificity { code: MISSING_LAYOUT_ATTRIBUTES specificity: 48 }
error_specificity { code: IMPLIED_LAYOUT_INVALID specificity: 49 }
error_specificity { code: SPECIFIED_LAYOUT_INVALID specificity: 50 }
error_specificity { code: ATTR_DISALLOWED_BY_IMPLIED_LAYOUT specificity: 51 }
error_specificity { code: ATTR_DISALLOWED_BY_SPECIFIED_LAYOUT specificity: 52 }
error_specificity { code: DUPLICATE_DIMENSION specificity: 53 }
error_specificity { code: DISALLOWED_RELATIVE_URL specificity: 54 }
error_specificity { code: MISSING_URL specificity: 55 }
error_specificity { code: DISALLOWED_DOMAIN specificity: 56 }
error_specificity { code: INVALID_URL_PROTOCOL specificity: 57 }
error_specificity { code: INVALID_URL specificity: 58 }
error_specificity { code: DISALLOWED_STYLE_ATTR specificity: 59 }
error_specificity { code: CSS_SYNTAX_STRAY_TRAILING_BACKSLASH specificity: 60 }
error_specificity { code: CSS_SYNTAX_UNTERMINATED_COMMENT specificity: 61 }
error_specificity { code: CSS_SYNTAX_UNTERMINATED_STRING specificity: 62 }
error_specificity { code: CSS_SYNTAX_BAD_URL specificity: 63 }
error_specificity {
  code: CSS_SYNTAX_EOF_IN_PRELUDE_OF_QUALIFIED_RULE specificity: 64
}
error_specificity { code: CSS_SYNTAX_INVALID_DECLARATION specificity: 65 }
error_specificity { code: CSS_SYNTAX_INCOMPLETE_DECLARATION specificity: 66 }
error_specificity { code: CSS_SYNTAX_ERROR_IN_PSEUDO_SELECTOR specificity: 67 }
error_specificity { code: CSS_SYNTAX_MISSING_SELECTOR specificity: 68 }
error_specificity { code: CSS_SYNTAX_NOT_A_SELECTOR_START specificity: 69 }
error_specificity {
  code: CSS_SYNTAX_UNPARSED_INPUT_REMAINS_IN_SELECTOR specificity: 70
}
error_specificity { code: CSS_SYNTAX_MISSING_URL specificity: 71 }
error_specificity { code: CSS_SYNTAX_DISALLOWED_DOMAIN specificity: 72 }
error_specificity { code: CSS_SYNTAX_INVALID_URL specificity: 73 }
error_specificity { code: CSS_SYNTAX_INVALID_URL_PROTOCOL specificity: 74 }
error_specificity { code: CSS_SYNTAX_DISALLOWED_RELATIVE_URL specificity: 75 }
error_specificity { code: INCORRECT_NUM_CHILD_TAGS specificity: 76 }
error_specificity { code: DISALLOWED_CHILD_TAG_NAME specificity: 77 }
error_specificity { code: DISALLOWED_FIRST_CHILD_TAG_NAME specificity: 78 }
error_specificity { code: CSS_SYNTAX_INVALID_ATTR_SELECTOR specificity: 79 }
error_specificity {
  code: CHILD_TAG_DOES_NOT_SATISFY_REFERENCE_POINT specificity: 80
}
error_specificity { code: MANDATORY_REFERENCE_POINT_MISSING specificity: 81 }
error_specificity { code: DUPLICATE_REFERENCE_POINT specificity: 82 }
error_specificity { code: TAG_REFERENCE_POINT_CONFLICT specificity: 83 }
error_specificity {
  code: CHILD_TAG_DOES_NOT_SATISFY_REFERENCE_POINT_SINGULAR
  specificity: 84
}
error_specificity { code: CSS_SYNTAX_DISALLOWED_PROPERTY_VALUE specificity: 85 }
error_specificity {
  code: CSS_SYNTAX_DISALLOWED_PROPERTY_VALUE_WITH_HINT
  specificity: 86
}
error_specificity {
  code: CSS_SYNTAX_PROPERTY_DISALLOWED_WITHIN_AT_RULE
  specificity: 87
}
error_specificity {
  code: CSS_SYNTAX_PROPERTY_DISALLOWED_TOGETHER_WITH
  specificity: 88
}
error_specificity {
  code: CSS_SYNTAX_PROPERTY_REQUIRES_QUALIFICATION
  specificity: 89
}
error_specificity {
  code: BASE_TAG_MUST_PRECEED_ALL_URLS
  specificity: 90
}
error_specificity { code: DISALLOWED_SCRIPT_TAG specificity: 102 }
error_specificity { code: GENERAL_DISALLOWED_TAG specificity: 103 }
error_specificity { code: DEPRECATED_ATTR specificity: 104 }
error_specificity { code: DEPRECATED_TAG specificity: 105 }
error_specificity { code: DISALLOWED_MANUFACTURED_BODY specificity: 106 }
error_specificity { code: DOCUMENT_TOO_COMPLEX specificity: 107 }
error_specificity { code: INCORRECT_MIN_NUM_CHILD_TAGS specificity: 108 }
error_specificity { code: TAG_NOT_ALLOWED_TO_HAVE_SIBLINGS specificity: 109 }
error_specificity { code: MANDATORY_LAST_CHILD_TAG specificity: 110 }
error_specificity {
  code: CSS_SYNTAX_INVALID_PROPERTY
  specificity: 111
}
error_specificity {
  code: CSS_SYNTAX_INVALID_PROPERTY_NOLIST
  specificity: 112
}
error_specificity {
  code: CSS_SYNTAX_QUALIFIED_RULE_HAS_NO_DECLARATIONS
  specificity: 113
}
error_specificity {
  code: CSS_SYNTAX_DISALLOWED_QUALIFIED_RULE_MUST_BE_INSIDE_KEYFRAME
  specificity: 114
}
error_specificity {
  code: CSS_SYNTAX_DISALLOWED_KEYFRAME_INSIDE_KEYFRAME
  specificity: 115
}
error_specificity {
  code: CSS_SYNTAX_MALFORMED_MEDIA_QUERY
  specificity: 117
}
error_specificity {
  code: CSS_SYNTAX_DISALLOWED_MEDIA_TYPE
  specificity: 118
}
error_specificity {
  code: CSS_SYNTAX_DISALLOWED_MEDIA_FEATURE
  specificity: 119
}
error_specificity {
  code: CSS_SYNTAX_DISALLOWED_ATTR_SELECTOR
  specificity: 120
}
error_specificity {
  code: CSS_SYNTAX_DISALLOWED_PSEUDO_CLASS
  specificity: 121
}
error_specificity {
  code: CSS_SYNTAX_DISALLOWED_PSEUDO_ELEMENT
  specificity: 122
}
error_specificity {
  code: CSS_SYNTAX_DISALLOWED_IMPORTANT
  specificity: 123
}
error_specificity {
  code: INVALID_UTF8
  specificity: 124
}
error_specificity {
  code: CSS_EXCESSIVELY_NESTED
  specificity: 125
}
error_specificity {
  code: DOCUMENT_SIZE_LIMIT_EXCEEDED
  specificity: 126
}
error_specificity {
  code: VALUE_SET_MISMATCH
  specificity: 127
}
error_specificity {
  code: INVALID_DOCTYPE_HTML
  specificity: 128
}
error_specificity {
  code: DEV_MODE_ONLY
  # This should always trump any other error. It is asserting
  # that the developer intends for this tag to be an error but
  # that no additional errors should be reported for this tag.
  specificity: 1000
}

# Error formats
error_formats {
  code: UNKNOWN_CODE
  format: "Unknown error."
}
error_formats {
  code: INVALID_DOCTYPE_HTML
  format: "Invalid or missing doctype declaration. Should be '!doctype html'."
}
error_formats {
  code: MANDATORY_TAG_MISSING
  format: "The mandatory tag '%1' is missing or incorrect."
}
error_formats {
  code: TAG_REQUIRED_BY_MISSING
  format: "The tag '%1' is missing or incorrect, but required by '%2'."
}
error_formats {
  code: WARNING_TAG_REQUIRED_BY_MISSING
  format: "The tag '%1' is missing or incorrect, but required by '%2'. "
          "This will soon be an error."
}
error_formats {
  code: TAG_EXCLUDED_BY_TAG
  format: "The tag '%1' is present, but is excluded by the presence of '%2'."
}
error_formats {
  code: WARNING_EXTENSION_UNUSED
  format: "The extension '%1' was found on this page, but is unused "
          "(no '%2' tag seen). This may become an error in the future."
}
error_formats {
  code: EXTENSION_UNUSED
  format: "The extension '%1' was found on this page, but is unused. "
          "Please remove this extension."
}
error_formats {
  code: WARNING_EXTENSION_DEPRECATED_VERSION
  format: "The extension '%1' is referenced at version '%2' which is a "
          "deprecated version. Please use a more recent version of this "
          "extension. This may become an error in the future."
}
error_formats {
  code: INVALID_EXTENSION_VERSION
  format: "The extension '%1' is referenced at version '%2' which is an "
          "invalid version. Please use a valid version of this "
          "extension."
}
error_formats {
  code: INVALID_EXTENSION_PATH
  format: "The extension '%1' has a path '%2' which is invalid. Please use "
          "a valid path for this extension."
}
error_formats {
  code: INCORRECT_SCRIPT_RELEASE_VERSION
  format: "The script version for '%1' is a %2 version which mismatches "
          "with the first script on the page using the %3 version."
}
error_formats {
  code: DISALLOWED_AMP_DOMAIN
  format: "The script tag includes an invalid AMP domain in the src attribute."
}
error_formats {
  code: NON_LTS_SCRIPT_AFTER_LTS
  format: "'%1' must use the LTS version to correspond with the first script "
          "in the page, which uses LTS."
}
error_formats {
  code: LTS_SCRIPT_AFTER_NON_LTS
  format: "'%1' must use the non-LTS version to correspond with the first "
          "script in the page, which does not use LTS."
}
error_formats {
  code: ATTR_REQUIRED_BUT_MISSING
  format: "The attribute '%1' in tag '%2' is missing or incorrect, but "
          "required by attribute '%3'."
}
error_formats {
  code: DISALLOWED_TAG
  format: "The tag '%1' is disallowed."
}
error_formats {
  code: GENERAL_DISALLOWED_TAG
  format: "The tag '%1' is disallowed except in specific forms."
}
error_formats {
  code: DISALLOWED_SCRIPT_TAG
  format: "Custom JavaScript is not allowed."
}
error_formats {
  code: DISALLOWED_ATTR
  format: "The attribute '%1' may not appear in tag '%2'."
}
error_formats {
  code: DISALLOWED_STYLE_ATTR
  format: "The inline 'style' attribute is not allowed in AMP documents. "
          "Use 'style amp-custom' tag instead."
}
error_formats {
  code: INVALID_ATTR_VALUE
  format: "The attribute '%1' in tag '%2' is set "
          "to the invalid value '%3'."
}
error_formats {
  code: DUPLICATE_ATTRIBUTE
  format: "The tag '%1' contains the attribute '%2' repeated multiple times."
}
error_formats {
  code: ATTR_VALUE_REQUIRED_BY_LAYOUT
  format: "Invalid value '%1' for attribute '%2' in tag '%3' - "
          "for layout '%4', set the attribute '%2' to value '%5'."
}
error_formats {
  code: MISSING_LAYOUT_ATTRIBUTES
  format: "Incomplete layout attributes specified for tag '%1'. For example, "
          "provide attributes 'width' and 'height'."
}
error_formats {
  code: IMPLIED_LAYOUT_INVALID
  format: "The implied layout '%1' is not supported by tag '%2'."
}
error_formats {
  code: SPECIFIED_LAYOUT_INVALID
  format: "The specified layout '%1' is not supported by tag '%2'."
}
error_formats {
  code: MANDATORY_ATTR_MISSING
  format: "The mandatory attribute '%1' is missing in tag '%2'."
}
error_formats {
  code: INCONSISTENT_UNITS_FOR_WIDTH_AND_HEIGHT
  format: "Inconsistent units for width and height in tag '%1' - "
          "width is specified in '%2' whereas height is specified in '%3'."
}
error_formats {
  code: STYLESHEET_TOO_LONG
  format: "The author stylesheet specified in tag '%1' is too "
          "long - document contains %2 bytes whereas the limit is %3 bytes."
}
error_formats {
  code: STYLESHEET_AND_INLINE_STYLE_TOO_LONG
  format: "The author stylesheet specified in tag 'style amp-custom' and "
          "the combined inline styles is too large - document contains %1 "
          "bytes whereas the limit is %2 bytes."
}
error_formats {
  code: INLINE_STYLE_TOO_LONG
  format: "The inline style specified in tag '%1' is too long - it "
          "contains %2 bytes whereas the limit is %3 bytes."
}
error_formats {
  code: INLINE_SCRIPT_TOO_LONG
  format: "The inline script is %1 bytes, which exceeds the limit of %2 bytes."
}
error_formats {
  code: MANDATORY_CDATA_MISSING_OR_INCORRECT
  format: "The mandatory text inside tag '%1' is missing or incorrect."
}
error_formats {
  code: CDATA_VIOLATES_DENYLIST
  format: "The text inside tag '%1' contains '%2', which is disallowed."
}
error_formats {
  code: NON_WHITESPACE_CDATA_ENCOUNTERED
  format: "The tag '%1' contains text, which is disallowed."
}
error_formats {
  code: INVALID_JSON_CDATA
  format: "The script tag contains invalid JSON that cannot be parsed."
}
error_formats {
  code: DISALLOWED_PROPERTY_IN_ATTR_VALUE
  format: "The property '%1' in attribute '%2' in tag '%3' is disallowed."
}
error_formats {
  code: INVALID_PROPERTY_VALUE_IN_ATTR_VALUE
  format: "The property '%1' in attribute '%2' in tag '%3' is set to "
          "'%4', which is invalid."
}
error_formats {
  code: DUPLICATE_DIMENSION
  format: "Multiple image candidates with the same width or pixel density "
          "found in attribute '%1' in tag '%2'."
}
error_formats {
  code: MISSING_URL
  format: "Missing URL for attribute '%1' in tag '%2'."
}
error_formats {
  code: INVALID_URL
  format: "Malformed URL '%3' for attribute '%1' in tag '%2'."
}
error_formats {
  code: INVALID_URL_PROTOCOL
  format: "Invalid URL protocol '%3:' for attribute '%1' in tag '%2'."
}
error_formats {
  code: DISALLOWED_DOMAIN
  format: "The domain '%3' for attribute '%1' in tag '%2' is disallowed."
}
error_formats {
  code: DISALLOWED_RELATIVE_URL
  format: "The relative URL '%3' for attribute '%1' in tag '%2' is disallowed."
}
error_formats {
  code: MANDATORY_PROPERTY_MISSING_FROM_ATTR_VALUE
  format: "The property '%1' is missing from attribute '%2' in tag '%3'."
}
error_formats {
  code: UNESCAPED_TEMPLATE_IN_ATTR_VALUE
  format: "The attribute '%1' in tag '%2' is set to '%3', which contains "
          "unescaped Mustache template syntax."
}
error_formats {
  code: TEMPLATE_PARTIAL_IN_ATTR_VALUE
  format: "The attribute '%1' in tag '%2' is set to '%3', which contains "
          "a Mustache template partial."
}
error_formats {
  code: DEPRECATED_TAG
  format: "The tag '%1' is deprecated - use '%2' instead."
}
error_formats {
  code: DEPRECATED_ATTR
  format: "The attribute '%1' in tag '%2' is deprecated - use '%3' instead."
}
error_formats {
  code: MUTUALLY_EXCLUSIVE_ATTRS
  format: "Mutually exclusive attributes encountered in tag '%1' - "
          "pick one of %2."
}
error_formats {
  code: MANDATORY_ONEOF_ATTR_MISSING
  format: "The tag '%1' is missing a mandatory attribute - pick one of %2."
}
error_formats {
  code: MANDATORY_ANYOF_ATTR_MISSING
  format: "The tag '%1' is missing a mandatory attribute - pick at least "
          "one of %2."
}
error_formats {
  code: WRONG_PARENT_TAG
  format: "The parent tag of tag '%1' is '%2', but it can only be '%3'."
}
error_formats {
  code: DISALLOWED_TAG_ANCESTOR
  format: "The tag '%1' may not appear as a descendant of tag '%2'."
}
error_formats {
  code: MANDATORY_TAG_ANCESTOR
  format: "The tag '%1' may only appear as a descendant of tag '%2'."
}
error_formats {
  code: MANDATORY_TAG_ANCESTOR_WITH_HINT
  format: "The tag '%1' may only appear as a descendant of tag '%2'. "
          "Did you mean '%3'?"
}
error_formats {
  code: DUPLICATE_UNIQUE_TAG
  format: "The tag '%1' appears more than once in the document."
}
error_formats {
  code: DUPLICATE_UNIQUE_TAG_WARNING
  format: "The tag '%1' appears more than once in the document. "
          "This will soon be an error."
}
error_formats {
  code: TEMPLATE_IN_ATTR_NAME
  format: "Mustache template syntax in attribute name '%1' in tag '%2'."
}
error_formats {
  code: ATTR_DISALLOWED_BY_IMPLIED_LAYOUT
  format: "The attribute '%1' in tag '%2' is disallowed by implied layout '%3'."
}
error_formats {
  code: ATTR_DISALLOWED_BY_SPECIFIED_LAYOUT
  format: "The attribute '%1' in tag '%2' is disallowed by specified "
          "layout '%3'."
}
error_formats {
  code: INCORRECT_NUM_CHILD_TAGS
  format: "Tag '%1' must have %2 child tags - saw %3 child tags."
}
error_formats {
  code: INCORRECT_MIN_NUM_CHILD_TAGS
  format: "Tag '%1' must have a minimum of %2 child tags - saw %3 child tags."
}
error_formats {
  code: TAG_NOT_ALLOWED_TO_HAVE_SIBLINGS
  format: "Tag '%1' is not allowed to have any sibling tags ('%2' should only"
  " have 1 child)."
}
error_formats {
  code: MANDATORY_LAST_CHILD_TAG
  format: "Tag '%1', if present, must be the last child of tag '%2'."
}
error_formats {
  code: DISALLOWED_CHILD_TAG_NAME
  format: "Tag '%1' is disallowed as child of tag '%2'. "
          "Child tag must be one of %3."
}
error_formats {
  code: DISALLOWED_FIRST_CHILD_TAG_NAME
  format: "Tag '%1' is disallowed as first child of tag '%2'. "
          "First child tag must be one of %3."
}
error_formats {
  code: DISALLOWED_MANUFACTURED_BODY
  format: "Tag or text which is only allowed inside the body section found "
          "outside of the body section."
}
error_formats {
  code: CHILD_TAG_DOES_NOT_SATISFY_REFERENCE_POINT
  format: "The tag '%1', a child tag of '%2', does not satisfy one of "
          "the acceptable reference points: %3."
}
error_formats {
  code: CHILD_TAG_DOES_NOT_SATISFY_REFERENCE_POINT_SINGULAR
  format: "The tag '%1', a child tag of '%2', does not satisfy "
          "the reference point '%3'."
}
error_formats {
  code: MANDATORY_REFERENCE_POINT_MISSING
  format: "The mandatory reference point '%1' for '%2' is missing."
}
error_formats {
  code: DUPLICATE_REFERENCE_POINT
  format: "The reference point '%1' for '%2' must be unique "
          "but a duplicate was encountered."
}
error_formats {
  code: TAG_REFERENCE_POINT_CONFLICT
  format: "The tag '%1' conflicts with reference point '%2' because "
          "both define reference points."
}
error_formats {
  code: BASE_TAG_MUST_PRECEED_ALL_URLS
  format: "The tag '%1', which contains URLs, was found earlier in the "
          "document than the BASE element."
}
error_formats {
  code: MISSING_REQUIRED_EXTENSION
  format: "The tag '%1' requires including the '%2' extension JavaScript."
}
error_formats {
  code: ATTR_MISSING_REQUIRED_EXTENSION
  format: "The attribute '%1' requires including the '%2' extension JavaScript."
}
error_formats {
  code: DOCUMENT_TOO_COMPLEX
  format: "The document is too complex."
}
error_formats {
  code: INVALID_UTF8
  format: "The document contains invalid UTF8."
}

# CSS Errors. All of these use %1 for the tag name (in practice 'style'
# by default).
error_formats {
  code: CSS_SYNTAX_INVALID_AT_RULE
  format: "CSS syntax error in tag '%1' - saw invalid at rule '@%2'."
}
error_formats {
  code: CSS_SYNTAX_STRAY_TRAILING_BACKSLASH
  format: "CSS syntax error in tag '%1' - stray trailing backslash."
}
error_formats {
  code: CSS_SYNTAX_UNTERMINATED_COMMENT
  format: "CSS syntax error in tag '%1' - unterminated comment."
}
error_formats {
  code: CSS_SYNTAX_UNTERMINATED_STRING
  format: "CSS syntax error in tag '%1' - unterminated string."
}
error_formats {
  code: CSS_SYNTAX_BAD_URL
  format: "CSS syntax error in tag '%1' - bad url."
}
error_formats {
  code: CSS_SYNTAX_EOF_IN_PRELUDE_OF_QUALIFIED_RULE
  format: "CSS syntax error in tag '%1' - end of stylesheet encountered "
          "in prelude of a qualified rule."
}
error_formats {
  code: CSS_SYNTAX_INVALID_PROPERTY
  format: "CSS syntax error in tag '%1' - invalid property '%2'. The only "
          "allowed properties are '%3'."
}
error_formats {
  code: CSS_SYNTAX_INVALID_PROPERTY_NOLIST
  format: "CSS syntax error in tag '%1' - invalid property '%2'."
}
error_formats {
  code: CSS_SYNTAX_QUALIFIED_RULE_HAS_NO_DECLARATIONS
  format: "CSS syntax error in tag '%1' - qualified rule '%2' has no "
          "declarations."
}
error_formats {
  code: CSS_SYNTAX_DISALLOWED_QUALIFIED_RULE_MUST_BE_INSIDE_KEYFRAME
  format: "CSS syntax error in tag '%1' - qualified rule '%2' must be located "
          "inside of a keyframe."
}
error_formats {
  code: CSS_SYNTAX_DISALLOWED_KEYFRAME_INSIDE_KEYFRAME
  format: "CSS syntax error in tag '%1' - keyframe inside keyframe is not "
          "allowed."
}
error_formats {
  code: CSS_SYNTAX_INVALID_DECLARATION
  format: "CSS syntax error in tag '%1' - invalid declaration."
}
error_formats {
  code: CSS_SYNTAX_INCOMPLETE_DECLARATION
  format: "CSS syntax error in tag '%1' - incomplete declaration."
}
error_formats {
  code: CSS_SYNTAX_ERROR_IN_PSEUDO_SELECTOR
  format: "CSS syntax error in tag '%1' - invalid pseudo selector."
}
error_formats {
  code: CSS_SYNTAX_MISSING_SELECTOR
  format: "CSS syntax error in tag '%1' - missing selector."
}
error_formats {
  code: CSS_SYNTAX_NOT_A_SELECTOR_START
  format: "CSS syntax error in tag '%1' - not a selector start."
}
error_formats {
  code: CSS_SYNTAX_UNPARSED_INPUT_REMAINS_IN_SELECTOR
  format: "CSS syntax error in tag '%1' - unparsed input remains in selector."
}
error_formats {
  code: CSS_SYNTAX_MISSING_URL
  format: "CSS syntax error in tag '%1' - missing url."
}
error_formats {
  code: CSS_SYNTAX_INVALID_URL
  format: "CSS syntax error in tag '%1' - invalid url '%2'."
}
error_formats {
  code: CSS_SYNTAX_INVALID_URL_PROTOCOL
  format: "CSS syntax error in tag '%1' - invalid url protocol '%2:'."
}
error_formats {
  code: CSS_SYNTAX_DISALLOWED_DOMAIN
  format: "CSS syntax error in tag '%1' - invalid domain '%2'."
}
error_formats {
  code: CSS_SYNTAX_DISALLOWED_RELATIVE_URL
  format: "CSS syntax error in tag '%1' - disallowed relative url '%2'."
}
error_formats {
  code: CSS_SYNTAX_INVALID_ATTR_SELECTOR
  format: "CSS syntax error in tag '%1' - invalid attribute selector."
}
error_formats {
  code: CSS_SYNTAX_DISALLOWED_PROPERTY_VALUE
  format: "CSS syntax error in tag '%1' - the property '%2' is set "
          "to the disallowed value '%3'."
}
error_formats {
  code: CSS_SYNTAX_DISALLOWED_PROPERTY_VALUE_WITH_HINT
  format: "CSS syntax error in tag '%1' - the property '%2' is set "
          "to the disallowed value '%3'. Allowed values: %4."
}
error_formats {
  code: CSS_SYNTAX_DISALLOWED_IMPORTANT
  format: "Usage of the !important CSS qualifier is not allowed."
}
error_formats {
  code: CSS_SYNTAX_PROPERTY_DISALLOWED_WITHIN_AT_RULE
  format: "CSS syntax error in tag '%1' - the property '%2' is disallowed "
          "within @%3. Allowed properties: %4."
}
error_formats {
  code: CSS_SYNTAX_PROPERTY_DISALLOWED_TOGETHER_WITH
  format: "CSS syntax error in tag '%1' - the property '%2' is disallowed "
          "together with '%3'. Allowed properties: %4."
}
error_formats {
  code: CSS_SYNTAX_PROPERTY_REQUIRES_QUALIFICATION
  format: "CSS syntax error in tag '%1' - the property '%2' is disallowed "
          "unless the enclosing rule is prefixed with the '%3' qualification."
}
error_formats {
  code: CSS_SYNTAX_MALFORMED_MEDIA_QUERY
  format: "CSS syntax error in tag '%1' - malformed media query."
}
error_formats {
  code: CSS_SYNTAX_DISALLOWED_MEDIA_TYPE
  format: "CSS syntax error in tag '%1' - disallowed media type '%2'."
}
error_formats {
  code: CSS_SYNTAX_DISALLOWED_MEDIA_FEATURE
  format: "CSS syntax error in tag '%1' - disallowed media feature '%2'."
}
error_formats {
  code: CSS_SYNTAX_DISALLOWED_ATTR_SELECTOR
  format: "CSS error in tag '%1' - disallowed attribute selector '%2'."
}
error_formats {
  code: CSS_SYNTAX_DISALLOWED_PSEUDO_CLASS
  format: "CSS error in tag '%1' - disallowed pseudo class '%2'."
}
error_formats {
  code: CSS_SYNTAX_DISALLOWED_PSEUDO_ELEMENT
  format: "CSS error in tag '%1' - disallowed pseudo element '%2'."
}
error_formats {
  code: CSS_EXCESSIVELY_NESTED
  format: "CSS excessively nested in tag '%1'."
}
error_formats {
  code: DOCUMENT_SIZE_LIMIT_EXCEEDED
  format: "Document exceeded %1 bytes limit. Actual size %2 bytes."
}
error_formats {
  code: VALUE_SET_MISMATCH
  format: "Attribute '%1' in tag '%2' contains a value that does not match any "
          "other tags on the page."
}
error_formats {
  code: DEV_MODE_ONLY
  format: "Tag 'html' marked with attribute 'data-ampdevmode'. Validator "
          "will suppress errors regarding any other tag with this attribute."
}
error_formats {
  code: AMP_EMAIL_MISSING_STRICT_CSS_ATTR
  format: "Tag 'html' marked with attribute 'amp4email' is missing the "
          "corresponding attribute 'data-css-strict' for enabling strict "
          "CSS validation. This may become an error in the future."
}