Delete butlast, nbutlast.

man/cl.texi

@@ -299,7 +299,7 @@ they do not cause other components like @file{cl-extra} to be loaded.
 @example
 eql           floatp-safe   endp
 evenp         oddp          plusp         minusp
-butlast       nbutlast      caaar .. cddddr
+caaar .. cddddr
 list*         ldiff         rest          first .. tenth
 copy-list     subst         mapcar* [2]
 adjoin [3]    acons         pairlis       pop [4]
@@ -4207,20 +4207,6 @@ The Emacs function @code{last} does the same thing
 except that it does not handle the optional argument @var{n}.
 @end defun
 
-@defun butlast x &optional n
-This function returns the list @var{x} with the last element,
-or the last @var{n} elements, removed.  If @var{n} is greater
-than zero it makes a copy of the list so as not to damage the
-original list.  In general, @code{(append (butlast @var{x} @var{n})
-(last @var{x} @var{n}))} will return a list equal to @var{x}.
-@end defun
-
-@defun nbutlast x &optional n
-This is a version of @code{butlast} that works by destructively
-modifying the @code{cdr} of the appropriate element, rather than
-making a copy of the list.
-@end defun
-
 @defun list* arg &rest others
 This function constructs a list of its arguments.  The final
 argument becomes the @code{cdr} of the last cell constructed.