I had high hopes for this. On some sites, moving the slider causes the video to restart. A small annoyance, but at least it worked. But after a couple minutes of testing it on various sites, it stopped working. Whenever I clicked on the icon, it would load a 'File not found' page that said, "Firefox can’t find the file at moz-extension://0ce5a5d8-195b-4581-9e31-65875b0c763a/popup/opt-in-en.html." There's clearly some leftover code that references junk from the original extension with no way for me to fix it.