@marco
1) I use #Molly-FOSS, which does not have any Google code and supports UnifiedPush
2) Doesn't Signal use FCM?
3) If the Signal Foundation controls both the running and development of the only server and the development of the only client, then the system is no longer secure against the second party, which obviates the point of end-to-end encryption. Signal can backdoor the Signal app to access your messages, contrary to their claim that not even they can access your messages. @signalapp