The URL at the bottom of the RPM manpage is bogus, and doesn't work. (That's <http://www.redhat.com/rpm/>) (Also the documentation seems to be incomplete but it's hard to call that a bug. :-)) Thanks...
This has been verified to be a bug. It has been assigned to a developer.
Fixed in rpm-2.5.x (rpm-2.90.x was already ok)