A fedora is a type of helm. The Archeologist role starts out with one, as an homage to Indiana Jones. It is never randomly generated.
Due to its lack of special ability or AC benefit, the fedora is often ditched at the beginning of the game. (It also has no value when dropped in a shop.)
In SLASH'EM the fedora is more useful, as it increases charisma by one and prevents good luck from timing out, in the same way a blessed luckstone does (but does not grant bonus luck).