Default is to have some limited universal filter (Google ads, etc) plus filters for regions your computer is set to. You can go into addon settings to activate filters for additional languages.
Most available maintained lists will show in the settings menu. There’s a few additional ones you can find by googling, then you add the filter URL for it in the settings.
Relativity works when earth is the center because it’s relative, we just calculate everything with earth as the frame of reference. It does make a lot of math harder, but that’s what we already are doing when using earth based telescopes (although we try to shift the math to a more reasonable frame of reference for most stuff, but earth is always the starting point because we’re making all the measurements from here)
That’s because the party isn’t a government institution, and candidates can run as independent (which does lower their chances, but the law don’t care about that part)