[Fnoord]

VLC has a feature called "float on top". Together with resizing, it allows basically something akin to picture in picture mode. You can use VLC to play YouTube videos by downloading them with youtube-dl. That is what I used before Firefox PiP mode was available in stable.

[aasasd]

VLC can play YouTube directly―at least if YouTube didn't change the format again. Just ‘open’ the URL as a network source.

[anticensor]

They changed the playlist format. It has been failing again.