What is the issue with the HTML Standard?

https://html.spec.whatwg.org/#dedicated-workers-and-the-worker-interface defines the onmessageerror event handler attribute for Worker, but can a "messageerror" event actually fire on a Worker object?

I have looked at all instances of "messageerror" and can't find any that seems to fire the event at an Worker instance, only other kinds of objects. Perhaps it happens implicitly through bubbling?

The only test I can find in WPT that listens for the event is https://wpt.fyi/results/webmessaging/broadcastchannel/workers.html, but only to fail the test if it is fired.

I'm trying to understand what behavior (if any) is required by the spec and how to test it, since it's not in Chrome but is in Firefox and Safari:
https://developer.mozilla.org/en-US/docs/Web/API/Worker#browser_compatibility