diff -r 7b81a535ad14 Doc/c-api/typeobj.rst
--- a/Doc/c-api/typeobj.rst	Wed Jul 17 13:41:39 2013 +0200
+++ b/Doc/c-api/typeobj.rst	Wed Jul 17 17:27:47 2013 +0200
@@ -464,6 +464,23 @@
       the following bits: :const:`Py_TPFLAGS_HAVE_STACKLESS_EXTENSION`,
       :const:`Py_TPFLAGS_HAVE_VERSION_TAG`.
 
+   .. data:: Py_TPFLAGS_LONG_SUBCLASS
+   .. data:: Py_TPFLAGS_LIST_SUBCLASS
+   .. data:: Py_TPFLAGS_TUPLE_SUBCLASS
+   .. data:: Py_TPFLAGS_BYTES_SUBCLASS
+   .. data:: Py_TPFLAGS_UNICODE_SUBCLASS
+   .. data:: Py_TPFLAGS_DICT_SUBCLASS
+   .. data:: Py_TPFLAGS_BASE_EXC_SUBCLASS
+   .. data:: Py_TPFLAGS_TYPE_SUBCLASS
+
+      These flags are used by functions such as
+      :c:func:`PyLong_Check` to quickly determine if a type is a subclass
+      of a built-in type; such specific checks are faster than a generic
+      check, like :c:func:`PyObject_IsInstance`. Custom types
+      that inherit from built-ins should have their :attr:`tp_flags` set
+      appropriately, or the code that interacts with such types
+      will behave differently depending on what kind of check is used.
+
 
 .. c:member:: char* PyTypeObject.tp_doc