jdironman parent
What about the server portion? that's the thing I would like to have forked / open source.
Good news! https://github.com/signalapp/Signal-Server
But is there federation between instances of this and the official signal servers?
There will likely never be federation between Signal's official servers and any other servers. Signal introduces privacy features semiregularly; we all saw with Matrix how difficult that is in a highly-federated environment.