Variable: mail-source-incoming-file-prefix
mail-source-incoming-file-prefix is a customizable variable defined in
mail-source.el.gz.
Value
"Incoming"
Documentation
Prefix for file name for storing incoming mail.
Source Code
;; Defined in /usr/src/emacs/lisp/gnus/mail-source.el.gz
(defcustom mail-source-incoming-file-prefix "Incoming"
"Prefix for file name for storing incoming mail."
:type 'string)