Variable: display-time-day-and-date
display-time-day-and-date is a customizable variable defined in
time.el.gz.
Value
nil
Documentation
Non-nil means M-x display-time (display-time) should display day and date as well as time.
Probably introduced at or before Emacs version 16.
Source Code
;; Defined in /usr/src/emacs/lisp/time.el.gz
;;;###autoload
(defcustom display-time-day-and-date nil "\
Non-nil means \\[display-time] should display day and date as well as time."
:type 'boolean)