We recently noticed on the mailing list a case where a message wasn't
properly connected to its parent. We should fix that of course.
ojwb> cworth: if you set the check_at_least parameter to the
database size, get_matches_estimated() will be exact
+Fix the threading of a message that has a References: header but no
+In-Reply-To: header (see id:"87lixxnxpb.fsf@yoom.home.cworth.org").
+
Search syntax
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Implement support for "tag:*" to expand to all tags.