Comment by vaylian

> Useful federation between Forgejo instances could be solved with little more than OIDC and a few webhooks (cross-instance collaboration, forking, and PRs).

That would only solve the problem of "I don't have an account on this forge yet". The much more relevant problem is identity + reputation. With ActivityPub-based federation you can use your domain-bound identifier to contribute to various projects across servers and gain reputation and trust. If we use OIDC, then it is a lot less clear if the server, you authenticate with, is hosting the real franga2000.