[delf]

GitSocial allows cross-forge collaboration without any 3rd party dependencies as it keeps everything in git: <https://github.com/gitsocial-org/gitsocial/blob/main/documen...>

Git IS the federation layer in this case.

[embedding-shape]

How do you authenticate the identity when people are submitting patches between two repositories running on two different servers?

[delf]

There's a federated identity spec and implementation: https://github.com/gitsocial-org/gitsocial/blob/main/documen.... For GH/GL, just an api call to verify signature, for custom domains, it's .well-known/gitmsg-id.json