Type: boolean
Default: yes
This variable is only useful when sorting by threads with `` $strict_threads'' unset. In that case, it changes the heuristic mutt uses to thread messages by subject. With sort_re set, mutt will only attach a message as the child of another message by subject if the subject of the child message starts with a substring matching the setting of `` $reply_regexp''. With sort_re unset, mutt will attach the message whether or not this is the case, as long as the non-`` $reply_regexp'' parts of both messages are identical.