Click to FreeTube by Andrei Ionel (thetechdog)

Heads up: For this extension to work, you must have FreeTube installed on your computer.

Click to FreeTube is a very simple Firefox extension that opens the current YouTube video or short in FreeTube while only asking for a minimal set of permissions.

Weaker hardware can struggle to play videos on YouTube properly, as the site itself can be pretty heavy.
You could just use FreeTube directly, but perhaps you want to have your personalized feed, so you still end up browsing on YouTube's website.

This extension (preferably paired with another extension that can stop the foreground video from automatically playing) can help you get the best of both worlds.

Simply click the extension's icon while on a YouTube video or short page and as long as FreeTube is properly installed, the video should open in FreeTube. This way you can keep browsing YouTube in your browser while enjoying smooth playback through FreeTube.