Check Mozilla support.

Access your data for all websites

The extension could read the content of any web page you visit, as well as data you enter into those web pages, such as usernames and passwords.

As mentioned by others, requires access to all websites when just youtube would be fine. And it does not work on Android at all.

Although being featured for Android, it doesn't work there.

Asking for access to all websites is too broad, considering only YouTube would be required.

We need a replacement for this for Android.

Hasn't worked for months now and won't update to new virsion even after uninstalling

For me I set this to 1080HD and every time it came up 1080HD which it never did before. But then I noticed I use Logitech options for the mouse gestures just skip back and it stopped working after checking around about config it wasn't that I disabled the extension and immediately all the keyboard shortcuts and gestures started working again and this was every website not just YouTube and it wasn't video related it was anything with the text form. Thought this was kick ass! even though the autoplay thing doesn't work oor drop down menu or any of the other settings work but it does set it to the highest resolution I've ever had. What's done install I'd rather have shortcuts I don't get it but it is what it is thanks anyway

This addon is a major security issue requiring access to data for ALL websites instead of just youtube. Dont trust it as there is absolutely no reason for that. Theres enhancer for youtube which does the same thing and more and only needs access to data on youtube in order to function correctly. Avoid!

No need to access data for all websites.