It works, that's everything to say about. Good replacement to the Persona changers I used back when this was a thing.
Would be great to have the ability to choose, which themes to be skipped. In my case it ultimatively skips the colored Firefox themes I downloaded to use along with the default dark, light, automatic and alpenglow ones I would agree on skipping as those can't be uninstalled.

A rotator that works, yay. This would be six stars if I could have it rotate on a timer while the browser is open. Please consider this functionality.

The only theme rotator I can find that actually works in current Firefox versions. My main request would be that the rotation could be on a timer instead of having to be at startup. (I can leave the browser up for days at a time.)