>Signal actually doesn't know all your contacts - you can check the source code to confirm that it doesn't know about any contacts that you don't message using Signal, for example.

I get a message in the app when a contact starts using Signal, so it has to know them server-side.

The other part of the comment was reffering to what the server could know (in the gov. case - will know), and that IS quite a lot (assuming Signal style service).

And I do trust Moxie nominally, but I also believe that he will obey US courts.