US government funding and markings are all over Signal.
The official app doesn’t make it clear how to connect to a custom server. As a self hosting enthusiast myself, I only found out it was possible when checking on your claim that it’s all open source.
You’re right, the server, cryptographic library, and all clients are open source.
That said, I have a few personal caveats.
I was talking entirely about Deepseek.
I never would have bothered to check because someone already pointed out Signal is US based but that is very interesting.
so thank you.