> The server implementation however is only based on trust in the people running the servers.

They literally chose a zero server trust model when designing the protocol. NSA could be running modified signal servers and it wouldn't make a difference. Your messages would still be safe since all the magic happens on the clients. The servers just route the encrypted data, it's all just 1's and 0's to them.

> And there, openness about the code at least gives a few hints about what is going on there, enabling me to trust at least a little more than not-at-all.

Do we even know if signal was running updated server code in production? Maybe they have been running the same code that was on github this whole time.