“Because everything in Signal is end-to-end encrypted by default, the broad set of personal information that is typically easy to retrieve in other apps simply doesn’t exist on Signal’s servers.”
Prosecutors asked Signal for names, addresses, messages and contacts. Signal had none of it to give. The only thing it can hand over is when an account was created and when it last connected. That is what end-to-end encryption looks like when a subpoena actually tests it.