trusted.pgp is a keyring containing all keys which PRZ has signed, all keys which those have signed, and so on. trusted.sig is a detached PGP signature for trusted.pgp. trusted.dat.gz is a gzipped listing of those keys in order of distance from the firstname.lastname@example.org key. For instance, those with distance 1 are signed by prz.acm. trusted.kv.gz is the output of pgp -kv "" trusted.pgp .
strong.pgp is a keyring containing all keys which are reachable to and from PRZ. That is, they have signed or have been signed by (possibly indirectly) email@example.com. strong.sig is a detached PGP signature for strong.pgp and strong.kv.gz is the output of pgp -kv "" strong.pgp .