Which key(s) is it signed with? What is the hash of the corresponding unsigned artifact?
Signature verification tools should have some option which prints these things in a machine-readable format.
I did some work on reproducibility of Android apps and system images with Nix, and while defining a build step which can automatically establish these relationships sounds a bit goofy, it can make the issues with underspecified edge cases visible by defining verification more strictly. I did not do this to look for those edge cases though.
I am still working on that type of stuff now, but on more fundamental issues of trust we could start addressing with systems like Nix.
i still believe "pgp is too complex" was the most successful cia counter action after they lost the crypto wars to the people.
solving via nix only works within the flawed assumptions that end users either fully trust google or fdroid and are incapable of anything else.
Thanks to the efforts of Google to "simplify" smartphones the average young person now couldn't find and double-click a downloaded file if their life depended on it.
In the US, a manual car is considered an anti-theft device. In Europe, basically everyone that isn't obscenely rich has driven a manual car at some point.
People learn what they're expected to learn.
However Whatsapp/signal show how e2e can be done in a user-compatible way. By default it simply exchanges keys and shows a warning when key is changed and those who need/want can verify identity.
Missing there of course openness.