https://html.spec.whatwg.org/multipage/embedded-content.html#error-codes This was discussed and added to HTML in January 2017: https://github.com/whatwg/html/issues/2085 https://github.com/whatwg/html/pull/2086 https://github.com/w3c/web-platform-tests/pull/4638 It is already in Gecko and about to ship in Chromium: https://github.com/mozilla/gecko-dev/blob/master/dom/webidl/MediaError.webidl https://groups.google.com/a/chromium.org/d/msg/blink-dev/yDIyWozG1xk/LKZqEkpoBAAJ
Shipped - https://github.com/WebKit/WebKit/commit/2556a110ed4c9447ed726dca20c919660743d701 *** This bug has been marked as a duplicate of bug 228008 ***