Variable: mh-thread-scan-line-map-stack
mh-thread-scan-line-map-stack is a buffer-local variable defined in
mh-e.el.gz.
Documentation
Old map of message index to various parts of the scan line.
This is the original map that is stored when the folder is narrowed.
Source Code
;; Defined in /usr/src/emacs/lisp/mh-e/mh-e.el.gz
(defvar mh-thread-scan-line-map-stack nil
"Old map of message index to various parts of the scan line.
This is the original map that is stored when the folder is
narrowed.")