I cannot yet give this app 5 stars, as it does not automatically play videos on taps in the foreground, if they were opened as background tabs first. (I'm watching a video, opening another in the background for later. After the current video is done, I switch to the other tab, but the video won't start.)

Edit: Okay, anybody fighting with the same issues as I, using Enhancer for YouTube, if you want to have the following happen on YouTube:

- Have foreground video playing automatically
- Have background (other tabs) videos not play automatically
- Have video play automatically on switching to it
- Starting a new video while an old one is still playing and having this automatically pause the old one

Then

1. disable the option "Automatically pause videos opened in background tabs" in Enhancer
2. tick "Pause videos playing in background tabs when a video starts playing in the foreground tab"
3. enter about:config into your search bar
4. search for media.autoplay.default and set to 0
5. search for media.block-autoplay-until-in-foreground and set to true