The ONLY one that works for FF! Even after 5.5 years. You have have restart FF before it works about half the time.

Now, why can't anyone else come up with another version that works ALL the time like they have on Chrome?

Does nothing. No matter if it's on or off, videos will automatically play when the page loads and will not stop until you hit the pause button. How worthless.

It's not working at all on Firefox

It used to work, but now, like other reviewers have said, it kills the YouTube channel home page entirely.

It is not working when open video in new table.

It does not work...

This one kills the YouTube channel home page entirely.

It works but it disables (breaks) my Youtube STOP button Add-on!

Не работает, не останавливает видео. Not work, autoplay still work

FINALLY! AN ADON THAT DOES WHAT IT'S SUPPOSED TO DO! THE USERS WILL TAKE THEIR WEB EXPERIENCE BACK FROM THESE WACK JOBS!

Работает, в отличии от других. По крайней мере на ютубе авто воспроизведение отключает.

Doesn't perform well enough for initial page load. There will be a brief second or two that the video would still play before it gets replaced by a non-playing video.

Just works.

None of the Youtube extensions have this functionality anymore, but the good news is this works perfectly alongside Enhancer and other extensions [atm].

Thank you very much!

This does not work on Firefox portable 63.0.3 (64-bit) on my computer. In the reviews of this app I found the best answer written by thomas glico. Editing about:config - media.autoplay.default 1 works perfectly.