-Invasive useIess toolbar button for one site.
-useIess bitmaps and large square.

The best adddon in its kind thats sadIy not updated is:

https://cup.aihedy.com/en-US/firefox/addon/youtube-auto-replay-11636/

OnIy opens the boxes you need when the main button
is clicked directly on any youtube video page.

Ok

I think you're the same creator for the repeat button on the old Youtube version, you could chose the time or loop the whole thing with the press of a button? It was great.

The problem right now is that your module affects every active Youtube tab, so brace yourself if you want to repeat something, EVERYTHING will be repeat at once.

I don't know how much restrictions you have right now to use an integrated button in the page, but it would be the better way to go. Plus I need to do a little math to find the time, no biggie, just not ideal.

I'd be happy to change my review once you have an integrated, tab specific, button.