If rolled out widely, this would make web browsers and third-party YouTube clients without a DRM license unusable for YouTube playback, download, etc. This would include almost all open-source web browsers and almost all third-party YouTube clients. Archive link to reddit post about this
Probably explains my looping 403 errors on SmartTube, but it eventually loads after several attempts.
It still isn’t working for me, apart from live streams
SmartTube?
I just let it roll through the 403 “Applying the fix”.error while I did something else. Took maybe 5–10 mins, but started playing and no issue since.