as symbols, but just returns them unchanged. It signals an error if
asked to copy markers.
-This function is used only while Emacs is being built and dumped; it is
-called only in the file @file{emacs/lisp/loaddefs.el}.
+This function is a no-op except while Emacs is being built and dumped;
+it is usually called only in the file @file{emacs/lisp/loaddefs.el}, but
+a few packages call it just in case you decide to preload them.
@end defun
@defvar pure-bytes-used