- * exist in the database. The caller can modify the message, and a
- * call to _notmuch_message_sync will add * the document to the
- * database.
+ * exist in the database. This message is "blank"; that is, it
+ * contains only a message ID and no other metadata. The caller
+ * can modify the message, and a call to _notmuch_message_sync
+ * will add the document to the database.