+
+# n.b. we silently ignore most per-message flags right now;
+# they're here for now to not dump parser errors.
+search_key1 : "ALL" | "ANSWERED" | "RECENT" | "UNSEEN" | "SEEN" | "NEW"
+ | "UNANSWERED" | "UNDELETED" | "UNDRAFT" | "UNFLAGGED"
+ | DELETED | DRAFT | FLAGGED | OLD