um, no? See the famous story of Hushmail [0], which used end-to-end encryption and claimed to have no access to user email until receiving a court order. Then they modified the code they send to one client to exfiltrate encryption keys to law enforcement, and decoded all the "end to end encrypted" email.
Sure, they claim they are open source and that the infrastructure was audited, but this does not prevent them from just configuring their auto-update server to serve a very special update to user at a specific IP.
Sure, they claim they are open source and that the infrastructure was audited, but this does not prevent them from just configuring their auto-update server to serve a very special update to user at a specific IP.
[0] https://www.wired.com/2007/11/encrypted-e-mai/