(defun undo-auto--boundaries (cause)
"Check recently changed buffers and add a boundary if necessary.
REASON describes the reason that the boundary is being added; see
-`undo-last-boundary' for more information."
+`undo-auto--last-boundary-cause' for more information."
;; (Bug #23785) All commands should ensure that there is an undo
;; boundary whether they have changed the current buffer or not.
(when (eq cause 'command)