part of the PSGI code and not need a separate daemon like
L<public-inbox-nntpd(1)> or L<public-inbox-imapd(1)>
+=item epoch
+
+A git repository used for blob storage. See
+L<public-inbox-v2-format(5)/GIT EPOCHS>.
+
=item keywords, (IMAP|Maildir) flags, mbox Status + X-Status
Private, per-message keywords or flags as described in RFC 8621