uninstalled. butthurt developer that can't take criticism. For everyone having received the same fate (know for a fact there are more), i found alternatives in the greasefork community.
plus, currently bugged anyway (march 2021)

Fantastic set of tools, a must-have for YouTube on desktop.

Sometimes I can't change the speed for the first video I open, it onlys shows xNaN, but reloading fixes the issue.
Apart from that, a very nice extension with lots of options

I started using it for its loop tool (which works flawlessly) but then started using more and more of the many tools available, like default resolution (super handy), detachable player, ad controls etc. Excellent Firefox extension.

Nice job. Lots of options to play with.

creo que el mejor add-on para youtube, aunque recomiendo un addblock de toda la vida para el tema de los anuncios