Variable: mh-thread-index-id-map
mh-thread-index-id-map is a buffer-local variable defined in
mh-thread.el.gz.
Documentation
Table to look up message identifier from message index.
Source Code
;; Defined in /usr/src/emacs/lisp/mh-e/mh-thread.el.gz
(defvar-local mh-thread-index-id-map nil
"Table to look up message identifier from message index.")