Document the -J and -X options for CPython. Note that unlike for py2k, we

don't need to document -U becuase it's gone in py3k.

Doc/using/cmdline.rst

@@ -238,8 +238,6 @@ Miscellaneous options
    See also :envvar:`PYTHONUNBUFFERED`.
 
 
-.. XXX should the -U option be documented?
-
 .. cmdoption:: -v
 
    Print a message each time a module is initialized, showing the place
@@ -315,6 +313,20 @@ Miscellaneous options
 
    .. note:: The line numbers in error messages will be off by one.
 
+Options you shouldn't use
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. cmdoption:: -J
+
+   Reserved for use by Jython_.
+
+.. _Jython: http://jython.org
+
+.. cmdoption:: -X
+
+    Reserved for alternative implementations of Python to use for their own
+    purposes.
+
 .. _using-on-envvars:
 
 Environment variables

Misc/NEWS

@@ -701,6 +701,9 @@ Build
 Documentation
 ------------
 
+- Updating `Using Python` documentation to include description of CPython's
+  -J and -X options.
+
 - Document that importing a module that has None in sys.modules triggers an
   ImportError.