Variable: rmail-secondary-file-directory
rmail-secondary-file-directory is a customizable variable defined in
rmail.el.gz.
Value
"~/"
Documentation
Directory for additional secondary Rmail files.
Probably introduced at or before Emacs version 19.24.
Source Code
;; Defined in /usr/src/emacs/lisp/mail/rmail.el.gz
;;;###autoload
(defcustom rmail-secondary-file-directory (purecopy "~/")
"Directory for additional secondary Rmail files."
:type 'directory
:group 'rmail-files)