-Message input format: C<eml>, C<maildir>, C<imap>, C<imaps>, C<nntp>,
-C<nntps>, C<mboxrd>, C<mboxcl2>, C<mboxcl>, or C<mboxo>.
+There is currently no need for this option. It will support C<mh>,
+eventually. For now, the default (and only supported) format is
+C<maildir>. When IMAP and NNTP support are fleshed out, those
+formats will be inferred from their URLs.