Oh ok I wasn't aware of that. I wonder why bridges like matrix-puppet-signal don't use it then. Because they currently run the full signal desktop app which is extremely wasteful if you're trying to run several bridges on your computer.

From what I understood from the LibreSignal discussion: Open Whisper Systems provides the source for transparency only, not to enable others to make clients for their service. They're free to build their own servers (which obviously will be unable to communicate with official Signal users!) but not connect to Signal itself.

The reason I keep pointing this out is that I'd really love for them to change their stance on this or at least allow federation from third-party Signal servers. It would really make it an open network. I don't want to move to something that is as locked-in as whatsapp as it is similarly dependent on their choices.