Maybe, or probably, but that means someone reverse-engineering what other browsers do and write a spec. So far that hasn't happened - it isn't exactly a trivial task.
Bug 1573801 Comment 9 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
Maybe, or probably, but that means someone reverse-engineering what other browsers do with contentEditable and write a spec. So far that hasn't happened - it isn't exactly a trivial task.