#17323: The "[X refs, Y blocks]" printed by debug builds has been disabled by default. It can be re-enabled with the `-X showrefcount` option.
diff --git a/Doc/using/cmdline.rst b/Doc/using/cmdline.rst
index 2703684..adb3739 100644
--- a/Doc/using/cmdline.rst
+++ b/Doc/using/cmdline.rst
@@ -358,13 +358,21 @@
.. cmdoption:: -X
Reserved for various implementation-specific options. CPython currently
- defines just one, you can use ``-X faulthander`` to enable
- :data:`faulthandler`. It also allows to pass arbitrary values and retrieve
- them through the :data:`sys._xoptions` dictionary.
+ defines two possible values:
+
+ * ``-X faulthander`` to enable :mod:`faulthandler`;
+ * ``-X showrefcount`` to enable the output of the total reference count
+ and memory blocks (only works on debug builds);
+
+ It also allows to pass arbitrary values and retrieve them through the
+ :data:`sys._xoptions` dictionary.
.. versionchanged:: 3.2
It is now allowed to pass :option:`-X` with CPython.
+ .. versionadded:: 3.4
+ The ``-X showrefcount`` option.
+
Options you shouldn't use
~~~~~~~~~~~~~~~~~~~~~~~~~