The extension is a bit messed up as of a few days ago, but it is ultimately the best YT addon out there so I'm here to support it.

Creator returned from not updating on firefox. Probably the best youtube enhancer around, as far as I could try.
Is there a way we could have cinema mode, hide the top bar (youtube, search bar, notifications and account), and be able to quickly access it by sliding the mouse at the top of the video to make it slide down or some such? Currently, you can scroll up to see it, but that just messes with the current video setup, forcing me to adjust it manually.

Would be 5 stars, but the "expand" function and themes recently stopped working

edit - 5 stars now, issues resolved

Really a shame that Mozilla took such draconian control over extensions, without the manpower to actually administer it, and made it so that developers can't push timely updates

Youtube broke the UI again, it is not the author's fault. This plugin works great always 5 stars

5 stars cause i love this addon and im looking forward to the theatre mode fix! :D

absolutely brilliant, checking up on this for the fix and decided to finally leave a well-deserved review :)

Thank you maxime for this amazing add-on, hope the updated version is released soon

Essential extension for Youtube viewing. Actively maintained and the dev does a good job keeping up with Youtube changes.

Excellent Add-on have been using it for years, cannot use Youtube without it anymore

I was wondering why the Youtube Player wasn't expanding anymore, but I found an answer here (to put it shortly, an update to Youtube broke it); knowing there's an update to the extension in the works and awaiting verification, I just want to say thank you for making the video viewing experience better.