Sometimes works, sometimes doesn't

You are a life saver

It plays in background, but often doesn't load the video in background.

Meh. More miss than hit

wow this works. thanks. Now I can turn on my phone display while m.youtube plays in BG

Why wasting money on buy YT Premium when you can use this add-on for free?
Support this add-on, support the openned web, support Firefox, my fellows