I made this userscript to play multiple videos from pirate streaming sites in sync (play/pause them at the same time)

usecase: You want to watch dubbed version of a movie (most people here probably watch in english, but may have friends or family members who don't). You find dubbed version, but in poor quality. Finding high quality english version is easy. You play the english version muted in foreground, and the dubbed version with audio in the background. With this userscript, you can play or pause them at the same time.

Not sure if anyone else finds it useful, but it' super useful for me, so I figured I'll share it here.