Overall good, so far. will be testing for myself. the fifth star is in queue!

Nice

good job, thank you

Works well, except volume control doesn't work until I refresh the page, or switch to another video.

would be nice if you could add an option, to show the rating (in percent) of a vid under the thumbnail. the rest is nice

add classic youtube design theme

nice tweaks for youtube. but that background tabs really wont stop playing u need extension background playback fix.

recently the miniplayer still appears despite being turned off

Pretty good, love the speed control. Would be great if you could set it to open music videos with 1.0 speed and other videos with the configured speed (maybe it could check the section video's in, music is usually in "Music" section).
Other than that, the biggest issue I have with it is that it doesn't seem to be free and open source.

様々な機能があり、重宝しています
ただ、ループ再生機能が一回しか効かなかったのと、
アンケートがスキップされなかったのが気になります。
また、画質の自動切換え機能で第二希望以下の画質に切り替わらないので、どういう基準で切り替わるのか謎です。

I would love it if this extension got a sharpness filter added, was a bit disappointed it wasn't one of the filter options.
Not to mention an integer based scaling option for people with 4k displays when watching 1080p videos, though I don't know if that's even possible.
A sharpness filter would help a lot though, since Nvidia's edge enhancement doesn't work in Firefox.

Does a wonderful job in most cases but does not stop youtube from auto playing in background tabs neither in firefox, chrome or opera. I think Youtube is overriding your setting somehow being the spammy ad monster it is.

One other small issue:
Sometimes videos don't start out in my preferred quality. I set it at 480p for this silly laptop, for instance). So videos wont even start because they're trying to play at 1080 or 720p instead. I noticed the same issue in Opera.

Works great, Thanks so much. :)
.. I even made a custom script to post a webhook
to a discord channel when i find a good vid.
Great custom script feature :)

it was working good, but recently it doesn't load videos at my preferred quality anymore