Chrome版は更新されているのにFirefox版は何ヶ月も放置されています。
更にYouTubeが新UIになり、当然そちらの対応もされておらず大変見苦しいので代替のアドオンを探した方がいいでしょう。

Przestał działać. Zamiast video odtwarza tylko dźwięk. Po wyłączeniu wtyczki film odtwarza się normalnie. Konieczna aktualizacja wtyczki!!!

Currently broken. You have to refresh a page after clicking for video window to show up. Will re-rate when fixed.

Unstable needs update. Seems to be abandoned since Nov 2024 (8 months ago). Screenshots are 1/2 1080p size.

Y'all really gotta update this. It's been months. Other browsers have been updated, but this one hasn't, and YouTube still looks broken.

I think we need a new update asap.

Will give it 5 stars when updated for Firefox.

In my "exodus from Chrome" I realy don't want to turn back to that hellhole just to not see shorts etc.

This extention is one of the better ones out there, but not up to date for Firefox (yet).
Let it happen, make it happen, make us happy and clean youtube-dwellers again :D