[upstream] Include an accessibility tester in CKEditor (axe, Tota11y, HTML Code Sniffer)

Sorry @quietone - I really think this needs to be a Drupal Core issue. There are some references to CKEditor 4, but this is bigger than that I think. Any development is going to happen in CKEditor 5 anyways.

I think it is an upstream issue though, as it should be addressed in CKEditor here - https://github.com/ckeditor/ckeditor5/issues/1941

It may just be that the approach is to talk to @itmaybejj about including Editoria11y in core.

Also definitely interested in @edmund.dunn's axe plugin.

@mgifford Does an accessibility tester exist for CKEditor 5?

No. Not yet. Which is why I marked it as Postponed.

To me that made more sense than moving this to a CKEditor 4 issue where it will become irrelevant.

Makes sense!

Tagging accordingly, to make it clear there's nothing actionable here right now.