You mean the GPG-signed client code?
Edit: On second thought, I recognize this whole subthread started with the wrong tone ("ironic", "reckless"), kind of dismissive or patronizing and not calling for a constructive discussion, so please disregard this comment of mine, sorry.
Considering there's no disadvantage in deploying HSTS and there's no good reason to serve an insecure website, especially since they already have HTTPS set up, I'm baffled by that decision. Maybe it's just an oversight but that's not too reassuring either.
HTTPS+HSTS adds no security here.
The only (reasonable) way to validate a payload end-to-end is an offline signature validation. This is true regardless of transport-level security measures like HTTPS.
Doing this properly with gpg makes even more sense due to the service targeting the paranoid, who is exactly the group of individuals who are certain to validate a signature.
> Considering there's no disadvantage in deploying HSTS and there's no good reason to serve an insecure website, especially since they already have HTTPS set up, I'm baffled by that decision. Maybe it's just an oversight but that's not too reassuring either.
It's easy, but adds nothing in ways of security here. Just privacy.
(Not that privacy does not have value, of course, but that's an entirely different argument.)
(However, Encrypted SNI is not widely adopted yet.)
Kind of a reckless decision.