+=item -E EXTINDEX
+
+=item --update-extindex=EXTINDEX
+
+Update the given external index (L<public-inbox-extindex-format(5)>.
+Either the configured section name (e.g. C<all>) or a directory name
+may be specified.
+
+Defaults to C<all> if C<[extindex "all"]> is configured,
+otherwise no external indices are updated.
+
+May be specified multiple times in rare cases where multiple
+external indices are configured.
+
+=item --no-update-extindex
+
+Do not update the C<all> external index by default. This negates
+all uses of C<-E> / C<--update-extindex=> on the command-line.
+
+=item --since=DATESTRING
+
+=item --after=DATESTRING
+
+=item --until=DATESTRING
+
+=item --before=DATESTRING
+
+Passed directly to L<git-log(1)> to limit changes for C<--reindex>
+