Hello Guix!
I've a proposal to make ‘guix publish’ somewhat extensible.
The draft patch allows for passing a list of ‘hooks’ to guix
publish, with "guix publish --hooks=FILE-WITH-HOOKS.scm
--hooks=MORE-HOOKS.go". "guix publish" then will consult
this list of hooks at some points.
I've defined a ‘narinfo-hook’, which allows adding extra
key value pairs to the generated narinfos. See the last
patch that adds a ‘hook.scm’ file for a silly example
that includes a random number and some arbitrary strings.