[bigfudge]

I love Signal, but in some jurisdictions government request for data can be accompanied by gagging orders with serious penalties for breach. I'm not sure that list can be considered complete.

[Forbo]

Does the design of Signal's applications or server infrastructure change because of the jurisdiction? Does the information they gather or store change?

[afiori]

With signal can you join public/private channels without disclosing your phone number?

The last time I checked (a few years back) I only saw private groups and no way to hide phone numbers.

If that is still the case then there are less reason to have a warrant for you phone number as it is easier to access.