I opened up an issue re: window.onerror on their previous bug tracker at the end of last year:

https://connect.microsoft.com/IE/feedbackdetail/view/2051728...

That issue has since been closed and "moved" to another URL. But the new URL is a broken link, and I cannot find the new issue via search (if it was created at all).

I've since spoken to Edge program managers about the issue, who've assured me it will be taken care of, but so far no progress has been made (possibly because it is no longer tracked).

(Raising this again here in hopes it will be noticed.)