Provide links to Python source where the code is short, readable and
informative adjunct to the docs.  Forward-port of Raymond's r86225 and
r86245 using the new source reST role added in #10334.
diff --git a/Doc/library/contextlib.rst b/Doc/library/contextlib.rst
index 35eb882..5e1a11a 100644
--- a/Doc/library/contextlib.rst
+++ b/Doc/library/contextlib.rst
@@ -9,6 +9,11 @@
 statement. For more information see also :ref:`typecontextmanager` and
 :ref:`context-managers`.
 
+.. seealso::
+
+   Latest version of the :source:`contextlib Python source code
+   <Lib/contextlib.py>`
+
 Functions provided: