Once the extension is installed and enabled, open the userscript to install it.
If something in the player appears broken, disable the script temporarily and reload the page to make sure it's not causing it. This is a good practice with any extension/userscript you install that modifies a website.
Keep volume bar visible
Put quality options on main bar
Hide quality options if there are no transcoders
F hotkey to toggle fullscreen
Easier access to stream stats
Keep track of seek position in VODs
(nothing to see here, feel free to send feature suggestions)