;; The threading portion of this files tries to implement the
;; algorithm described at:
;; http://www.jwz.org/doc/threading.html
-;; It also begins to implement the IMAP Threading extension RFC. The
-;; implementation lacks the reference and subject canonicalization of
-;; the RFC.
+;; It also begins to implement the threading section of the IMAP -
+;; SORT and THREAD Extensions RFC at:
+;; http://tools.ietf.org/html/rfc5256
+;; The implementation lacks the reference and subject canonicalization
+;; of the RFC.
;; In the presentation buffer, children messages are shown indented
;; with either [ ] or < > around them. Square brackets ([ ]) denote