+Our use of the L</OVERVIEW DB> requires Xapian document IDs to
+remain stable. Using L<public-inbox-compact(1)> and
+L<public-inbox-xcpdb(1)> wrappers are recommended over tools
+provided by Xapian.
+
+This directory is large, often two to three times the size of
+the objects stored in a packed git repository.
+