> 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.
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.