Variable: mh-show-mode-hook
mh-show-mode-hook is a customizable variable defined in mh-show.el.gz.
Value
nil
Documentation
Hook run upon entry to mh-show-mode.
This hook is called early on in the process of the message display,
before the message contents have been inserted into the buffer.
It is usually used to perform some action on the
buffer itself. See also mh-show-hook.
This variable was added, or its default value changed, in MH-E version
8.7.
Probably introduced at or before Emacs version 27.1.
Source Code
;; Defined in /usr/src/emacs/lisp/mh-e/mh-show.el.gz