Merge: #26829: Clarify that namespace is copied to a new __dict__ in instance creation.

Doc/library/functions.rst

@@ -1449,8 +1449,9 @@ are always available.  They are listed here in alphabetical order.
    class name and becomes the :attr:`~class.__name__` attribute; the *bases*
    tuple itemizes the base classes and becomes the :attr:`~class.__bases__`
    attribute; and the *dict* dictionary is the namespace containing definitions
-   for class body and becomes the :attr:`~object.__dict__` attribute.  For
+   for class body and is copied to a standard dictionary to become the
-   example, the following two statements create identical :class:`type` objects:
+   :attr:`~object.__dict__` attribute.  For example, the following two
+   statements create identical :class:`type` objects:
 
       >>> class X:
       ...     a = 1

Doc/reference/datamodel.rst

@@ -1735,6 +1735,11 @@ After the class object is created, it is passed to the class decorators
 included in the class definition (if any) and the resulting object is bound
 in the local namespace as the defined class.
 
+When a new class is created by ``type.__new__``, the object provided as the
+namespace parameter is copied to a standard Python dictionary and the original
+object is discarded. The new copy becomes the :attr:`~object.__dict__` attribute
+of the class object.
+
 .. seealso::
 
    :pep:`3135` - New super

Misc/ACKS

@@ -1007,6 +1007,7 @@ Peter Moody
 Paul Moore
 Ross Moore
 Ben Morgan
+Emily Morehouse
 Derek Morr
 James A Morrison
 Martin Morrison