I strongly echo many comments in this review area.
Maxim, please communicate to us regarding the difficulties involved in modifying "Enhancer for YouTube™ by Maxime RF" ( or modifying a recently compatible extension, in general, to achieve this ).
(( By the way, the following is your website, correct ? :
https://www.mrfdev.com/enhancer-for-youtube ))
so that it is correctly signed for current inclusion as an extension for Firefox Quantum ( a change in security for FF users since one of FF's most recent updates. I have
66.0.3 and about to UD to 66.0.4 in a couple mins.

Thank you for your time and your great extension,

Looking forward to your reply.

Auto theatre mod not working.

Whilst this extension does not have the issue of blocking youtube embeds used on video game pages, instead it is not compatible with lazy tab loading and where processes should only be spawned when tabs are selected, this extension causes all ipc processes to be created at start.

Please see https://bugzilla.mozilla.org/show_bug.cgi?id=906076 and adjust the extension to only touch loaded tabs.

Сделайте чтобы язык субтитров по умолчанию был русский или чтобы можно было выбирать язык по умолчанию а то он всегда сбрасывается на английский.

Meets all my expectations. I work in media.