Variable: dired-marker-char
dired-marker-char is a variable defined in dired.el.gz.
Value
42
Documentation
In Dired, the current mark character.
This is what the do-commands look for, and what the mark-commands store.
Source Code
;; Defined in /usr/src/emacs/lisp/dired.el.gz
;;; Internal variables
(defvar dired-marker-char ?* ; the answer is 42
;; so that you can write things like
;; (let ((dired-marker-char ?X))
;; ;; great code using X markers ...
;; )
;; For example, commands operating on two sets of files, A and B.
;; Or marking files with digits 0-9. This could implicate
;; concentric sets or an order for the marked files.
;; The code depends on dynamic scoping on the marker char.
"In Dired, the current mark character.
This is what the do-commands look for, and what the mark-commands store.")