Emacs undecorated (title-less) frame in OSX

toggle-frame-maximized-undecorated.el

(defun toggle-frame-maximized-undecorated ()
  (interactive)
  (let* ((frame (selected-frame))
         (on? (and (frame-parameter frame 'undecorated)
                   (eq (frame-parameter frame 'fullscreen) 'maximized)))
         (geom (frame-monitor-attribute 'geometry))
         (x (nth 0 geom))
         (y (nth 1 geom))
         (display-height (nth 3 geom))
         (display-width (nth 2 geom))
         (cut (if on?
                  (if ns-auto-hide-menu-bar 26 50)
                (if ns-auto-hide-menu-bar 4 26))))
    (set-frame-position frame x y)
    (set-frame-parameter frame 'fullscreen-restore 'maximized)
    (set-frame-parameter nil 'fullscreen 'maximized)
    (set-frame-parameter frame 'undecorated (not on?))
    (set-frame-height frame (- display-height cut) nil t)
    (set-frame-width frame (- display-width 20) nil t)
    (set-frame-position frame x y)))

Where are the first and second functions defined?

first and second are aliases for car and cadr,