It's a very nice extension but I get a weird issue on my galaxy note 20 - it works on wi-fi but not on mobile data. And it is not a connection issue, as soon as I disable extension, I can watch UT video via mobile data. But saving mobile data is exactly why I need this.

在手機上可以使用,在PC上不能使用..

At first it worked correctly, it does its purpose. But when I updated Firefox to its latest version and also installed Microsoft's AV1 add-on for Windows, it stopped working. Apparently it only works at the moment with the VP9 codec because I have it installed on my Android smartphone and it works correctly.

I tried Youtube Audio, didn't run videos. Changed to Youtube Audio_only, worked perfectly. The only handicap is that it gets a little bit slower to serve the video, but not so much