PEP 3147
diff --git a/Doc/library/runpy.rst b/Doc/library/runpy.rst
index 7278b7a..a96285c 100644
--- a/Doc/library/runpy.rst
+++ b/Doc/library/runpy.rst
@@ -32,7 +32,8 @@
    below are defined in the supplied dictionary, those definitions are
    overridden by :func:`run_module`.
 
-   The special global variables ``__name__``, ``__file__``, ``__loader__``
+   The special global variables ``__name__``, ``__file__``, ``__cached__``,
+   ``__loader__``
    and ``__package__`` are set in the globals dictionary before the module
    code is executed (Note that this is a minimal set of variables - other
    variables may be set implicitly as an interpreter implementation detail).
@@ -45,6 +46,8 @@
    loader does not make filename information available, this variable is set
    to :const:`None`.
 
+    ``__cached__`` will be set to ``None``.
+
    ``__loader__`` is set to the PEP 302 module loader used to retrieve the
    code for the module (This loader may be a wrapper around the standard
    import mechanism).