Deliverator
Graphical Hackificator
Well that's an unexpected side effect.
Does Asset Explorer work? (https://iowin.net/en/unity-assets-explorer/) Is it documented anywhere that Asset Studio doesn't work with 2021 or is it just something that people notice?
There are quite a lot of open issues describing the same error that I'm getting. I guess the creator didn't want to fix or maintain it anymore for whatever reason. I'll take a look at Asset Explorer.