+ tags: [string*],
+
+ # Two stable query strings identifying exactly the matched and
+ # unmatched messages currently in this thread. The messages
+ # matched by these queries will not change even if more messages
+ # arrive in the thread. If there are no matched or unmatched
+ # messages, the corresponding query will be null (there is no
+ # query that matches nothing). (Added in schema version 2.)
+ query: [string|null, string|null],