Holds your saved settings and flag, it will basically do a hard reset. You may have to start over too.
Well my UI has returned. I removed the persistent file and it's back, though in trying to test it being the cause and putting the file back, the UI remained, so who knows. Either way I can use it again. Sadly there's no recovering my saves anyway, so that's just bullet to bite regardless.
I didn't end up trying the other downloads at all.