=head1 TERMS
+=over 8
+
=item IMAP UID, NNTP article number, on-disk Xapian docid
A sequentially-assigned positive integer. These integers are per-inbox,
used, and then the current time if neither header exists.
When mirroring via git, this is the git author time.
+=back
+
=head1 COPYRIGHT
Copyright 2021 all contributors L<mailto:meta@public-inbox.org>