diff -r 3ae2cd85a908 Doc/reference/datamodel.rst
--- a/Doc/reference/datamodel.rst	Sun Mar 09 11:18:16 2014 +0100
+++ b/Doc/reference/datamodel.rst	Mon Mar 10 14:32:44 2014 +0530
@@ -1467,6 +1467,8 @@
    Called to delete the attribute on an instance *instance* of the owner class.
 
 
+The :attr:`__objclass__` is interpreted by the inspect module as specifying the class where this object was defined (setting this appropriately can assist in runtime introspection of dynamic class attributes). For callables, may indicate that an instance of the given type (or a subclass) is expected or required as the first positional argument (for example, CPython sets this for unbound methods that are implemented in C rather than being normal Python functions).
+
 .. _descriptor-invocation:
 
 Invoking Descriptors