=item --prune[=<local|remote>]
C<--prune> will forget saved searches if the C<OUTPUT> no longer
-exists. C<--all=local> only prunes local mailboxes,
-C<--all=remote> only prunes remote mailboxes (currently
+exists. C<--prune=local> only prunes local mailboxes,
+C<--prune=remote> only prunes remote mailboxes (currently
C<imap://> and C<imaps://>).
=back