You need to encode the metadata in a standard way, encode new data that shows up in a standard way, and various people can add more metadata to files: think like Posix ACLs or the immutable flag or whatever.

Nix actually invented a fork of tar specifically for this called “normalized archive” or “Nix Archive” or nar. Guix uses this too:

https://releases.nixos.org/nix/nix-2.22.0/manual/protocols/nix-archive.html

“here is a checksum of my /usr/lib folder, if yours differs from mine I can’t provide installation support”

For the people who are dunking on this by saying that historically things have been fucked up:

I think the point of the tweet is that systemic development doesn’t stop at capitalism.

I’m pretty sure lots of educated people during the feudal era were saying that it was the best system available and at least they were dying less often than the Romans.