@pixelfed is this specialized to *only* login from approved mastodon instances, rather than something like my OIDC patches for generic SSO?
https://github.com/pixelfed/pixelfed/pull/3436 
SSO OIDC client support by osresearch · Pull Request #3436 · pixelfed/pixelfed
This is a very early draft set of changes to integrate Single Sign On using OpenID Connect into PixelFed. This hacks together the GCS OIDC Client library with some glue to create user accounts bas...
GitHub