I recently failed to find a known procedure when searching
ALL_PROCEDURES, and on a whim tried
DBA_PROCEDURES: lo, there it is. The doc pages (ALL_; DBA_) both say "...lists all functions and procedures along with their associated properties." Oracle seems to have a curious definition of "all".
I'm posting this on DBA rather than SO, though it's a pretty basic question, on the basis that schema management is generally a DBA role rather than a developer role.