Variable: rmail-default-file
rmail-default-file is a customizable variable defined in rmail.el.gz.
Value
"~/xmail"
Documentation
Default file name for M-x rmail-output (rmail-output).
Source Code
;; Defined in /usr/src/emacs/lisp/mail/rmail.el.gz
;; Note that rmail-output-read-file-name modifies this.
(defcustom rmail-default-file "~/xmail"
"Default file name for \\[rmail-output]."
:type 'file
:group 'rmail-files)