diff -r 4d4277941a45 Doc/howto/urllib2.rst
--- a/Doc/howto/urllib2.rst	Fri Apr 12 23:30:59 2013 +0300
+++ b/Doc/howto/urllib2.rst	Sat Apr 13 13:55:42 2013 -0400
@@ -504,9 +504,10 @@
 
     In the above example we only supplied our ``HTTPBasicAuthHandler`` to
     ``build_opener``. By default openers have the handlers for normal situations
-    -- ``ProxyHandler``, ``UnknownHandler``, ``HTTPHandler``,
+    -- ``ProxyHandler`` (if a ``*_proxy`` environment variable like
+    :envvar:`http_proxy` is set), ``UnknownHandler``, ``HTTPHandler``,
     ``HTTPDefaultErrorHandler``, ``HTTPRedirectHandler``, ``FTPHandler``,
-    ``FileHandler``, ``HTTPErrorProcessor``.
+    ``FileHandler``, ``DataHandler``, ``HTTPErrorProcessor``.
 
 ``top_level_url`` is in fact *either* a full URL (including the 'http:' scheme
 component and the hostname and optionally the port number)
@@ -521,10 +522,12 @@
 =======
 
 **urllib** will auto-detect your proxy settings and use those. This is through
-the ``ProxyHandler`` which is part of the normal handler chain. Normally that's
-a good thing, but there are occasions when it may not be helpful [#]_. One way
-to do this is to setup our own ``ProxyHandler``, with no proxies defined. This
-is done using similar steps to setting up a `Basic Authentication`_ handler : ::
+the ``ProxyHandler`` which is part of the normal handler chain when a
+``*_proxy`` environment variable like :envvar:`http_proxy` is set. Normally
+that's a good thing, but there are occasions when it may not be helpful
+[#]_. One way to do this is to setup our own ``ProxyHandler``, with no proxies
+defined. This is done using similar steps to setting up a `Basic
+Authentication`_ handler : ::
 
     >>> proxy_support = urllib.request.ProxyHandler({})
     >>> opener = urllib.request.build_opener(proxy_support)
diff -r 4d4277941a45 Doc/library/urllib.request.rst
--- a/Doc/library/urllib.request.rst	Fri Apr 12 23:30:59 2013 +0300
+++ b/Doc/library/urllib.request.rst	Sat Apr 13 13:55:42 2013 -0400
@@ -87,8 +87,9 @@
    the default installed global :class:`OpenerDirector` uses
    :class:`UnknownHandler` to ensure this never happens).
 
-   In addition, default installed :class:`ProxyHandler` makes sure the requests
-   are handled through the proxy when they are set.
+   In addition, when a ``*_proxy`` environment variable like
+   :envvar:`http_proxy` is set, :class:`ProxyHandler` is default installed and
+   makes sure the requests are handled through the proxy.
 
    The legacy ``urllib.urlopen`` function from Python 2.6 and earlier has been
    discontinued; :func:`urllib.request.urlopen` corresponds to the old