mh-variant

mh-variant is a variable defined in `mh-e.el'.
Its value is

autodetect

Documentation:
*Specifies the variant used by MH-E.

The default setting of this option is "Auto-detect" which means
that MH-E will automatically choose the first of nmh, MH, or GNU
mailutils MH that it finds in the directories listed in
`mh-path' (which you can customize), `mh-sys-path', and
`exec-path'. If MH-E can't find MH at all, you may have to
customize `mh-path' and add the directory in which the command
"mhparam" is located. If, on the other hand, you have both nmh
and GNU mailutils MH installed (for example) and
`mh-variant-in-use' was initialized to nmh but you want to use
GNU mailutils MH, then you can set this option to "gnu-mh".

When this variable is changed, MH-E resets `mh-progs', `mh-lib',
`mh-lib-progs', `mh-flists-present-flag', and `mh-variant-in-use'
accordingly. Prior to version 8, it was often necessary to set
some of these variables in "~/.emacs"; now it is no longer
necessary and can actually cause problems.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 8.0 of the MH-E package that is part of Emacs 22.1.