Variable: mh-scan-msg-number-regexp
mh-scan-msg-number-regexp is a variable defined in mh-scan.el.gz.
Value
"^ *\\([0-9]+\\)"
Documentation
This regular expression extracts the message number.
It must match from the beginning of the line. Note that the message number must be placed in a parenthesized expression as in the default of "^ *\\\\([0-9]+\\\\)".
Source Code
;; Defined in /usr/src/emacs/lisp/mh-e/mh-scan.el.gz
(defvar mh-scan-msg-number-regexp "^ *\\([0-9]+\\)"
"This regular expression extracts the message number.
It must match from the beginning of the line. Note that the
message number must be placed in a parenthesized expression as in
the default of \"^ *\\\\([0-9]+\\\\)\".")