Schmidt's Katz by Cubimon

Control your music and videos with Schmidt's Katz's keyboard shortcuts. This plugin aims to be feature-complete - you can change volume, seek or even change the playback rate using keystroke commands. To use shortcuts outside Firefox, a native interface integrates this plugin into MPRIS on Linux.

This extension may be interesting for you, if you want to:
- work efficiently with music
- control music in a comfort way - you don't have to search tabs and do half a dozen mouse/keyboard actions
- be able to mute music immediately
- use a lot of tabs and easily lose the music tab

At the moment only Youtube works. Source code can be found on Github, any kind of contribution is welcome. Popup icons are from Fontawesome.