I put this in General because of the fact it affects every user and is a long-ongoing major annoyance, reported multiple times and totally obvious and reproducible, so we should finally at least create a workaround for it... Videos with wrong embed frame have a code like this: <iframe src="https://www.youtube-nocookie.com/embed/63qtYi1nwcs" style="border:none;" tc-textcontent="true" data-tc-id="w-0.7741963759265602" frameborder="0"></iframe> Videos with right embed frame have code like this: <iframe src="https://www.youtube-nocookie.com/embed/63qtYi1nwcs" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen="" tc-textcontent="true" data-tc-id="w-0.7741963759265602" width="480" height="270" frameborder="0"></iframe> I can just edit the page source code and add those bits and it works with any video, basically fixing the issue. Now, because for some incomprehensible reason CIG hasn't fixed this in years, I am once again trying to apply this addition automatically via browser addon. The one I found for it is FoxReplace, but it makes trouble. The replace syntax seems fine, but trigger by page load only doesn't work. 10-second interval also doesn't work except if I open a reply textbox. Then suddenly the addon applies the replace on the video embed in the OP. But this messes up reply functionality. Is it possible to do this better with Tampermonkey or such? (I wouldn't know how to write the script for that. It would also mean yet another browser addon running.)