mh-default-folder-prefix

mh-default-folder-prefix is a variable defined in `mh-e.el'.
Its value is

""

Documentation:
*Prefix used for folder names generated from aliases.
The prefix is used to prevent clutter in your mail directory.

See `mh-prompt-for-refile-folder' and `mh-folder-from-address'
for more information.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 7.2 of the MH-E package that is part of Emacs 22.1.