+The **lastmod:** prefix can be used to restrict the result by the
+database revision number of when messages were last modified (tags
+were added/removed or filenames changed). This is usually used in
+conjunction with the **--uuid** argument to **notmuch search**
+to find messages that have changed since an earlier query.
+
+The **query:** prefix allows queries to refer to previously saved
+queries added with **notmuch-config(1)**. Named queries are only
+available if notmuch is built with **Xapian Field Processors** (see
+below).
+
+The **property:** prefix searches for messages with a particular
+<key>=<value> property pair. Properties are used internally by notmuch
+(and extensions) to add metadata to messages. A given key can be
+present on a given message with several different values.
+