hi guys! this is NOT UPDATED since 2016 so a lot wont work.. Try Improvedtube.com tho ( ​https://github.com/code4charity/YouTube-Extension/blob/master/README.md ).
, it is the only big Youtube extension developed openly and since several years and Recommended By Firefox🦊 (the alternatives resigned along the way, because it requires continuous work)
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wszystko działa dobrze
everything works well

спасибо 5 звезд доступ к ютьюб

Muito bom e útil

Olá familiares do mundo virtual peso que entre no YouTube e digitar o meu nome ivan ademar de arruda

exelente!

good

super....................................