#652749: document the constants added to the builtins by site.py.
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 665b865..227b0fc 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -511,6 +511,8 @@
    topic, and a help page is printed on the console.  If the argument is any other
    kind of object, a help page on the object is generated.
 
+   This function is added to the built-in namespace by the :mod:`site` module.
+
    .. versionadded:: 2.2