mh-invisible-header-fields

mh-invisible-header-fields is a variable defined in `mh-e.el'.
Its value is

nil

Documentation:
*Additional header fields to hide.

Header fields that you would like to hide that aren't listed in
`mh-invisible-header-fields-default' can be added to this option
with a couple of caveats. Regular expressions are not allowed.
Unique fields should have a ":" suffix; otherwise, the element
can be used to render invisible an entire class of fields that
start with the same prefix.

If you think a header field should be generally ignored, please
update SF #1916032 (see URL
`https://sourceforge.net/tracker/index.php?func=detail&aid=1916032&group_id=13357&atid=113357').

See also `mh-clean-message-header-flag'.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 7.1 of the MH-E package that is part of Emacs 22.1.