Remove default GitHub credentials from VCS roots

Hi!

Every time I create a new project from GitHub, or even every time I use the GitHub icon next to Fetch URL when manually creating a new VCS root, it automatically sets Authentication to "Password / access token", and prefills it with some - to me - unknown password or token.

I don't remember if I ever gave TeamCity any GitHub credentials, but I cannot find any way to change it now. How do I tell TeamCity to always default to Anonymous authentication?