Fix for Issue7155 - urllib do not document default use of system proxy configuration

Doc/library/urllib.rst

@@ -96,8 +96,10 @@ High-level interface
 
    .. index:: single: Internet Config
 
-   In a Macintosh environment, :func:`urlopen` will retrieve proxy information from
-   Internet Config.
+   In a Mac OS X  environment, :func:`urlopen` will retrieve proxy information
+   from the OS X System Configuration Framework, which can be managed with
+   Network System Preferences panel.
+
 
    Alternatively, the optional *proxies* argument may be used to explicitly specify
    proxies.  It must be a dictionary mapping scheme names to proxy URLs, where an

Doc/library/urllib2.rst

@@ -53,6 +53,9 @@ The :mod:`urllib2` module defines the following functions:
    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.
+
    .. versionchanged:: 2.6
       *timeout* was added.
 
@@ -187,8 +190,13 @@ The following classes are provided:
 .. class:: ProxyHandler([proxies])
 
    Cause requests to go through a proxy. If *proxies* is given, it must be a
-   dictionary mapping protocol names to URLs of proxies. The default is to read the
-   list of proxies from the environment variables :envvar:`<protocol>_proxy`.
+   dictionary mapping protocol names to URLs of proxies. The default is to read
+   the list of proxies from the environment variables
+   :envvar:`<protocol>_proxy`.  If no proxy environment variables are set, in a
+   Windows environment, proxy settings are obtained from the registry's
+   Internet Settings section and in a Mac OS X  environment, proxy information
+   is retrieved from from the OS X System Configuration Framework.
+
    To disable autodetected proxy pass an empty dictionary.