[Victor]
'''Oh, collections.abc contains also the mappingview type exposed with the name "dict_proxy": dict_proxy = type(type.__dict__)

It was exposed as _abcoll.dict_proxy in Python 3.2.
It is not documented. Should we keep it for backward compatibility, or can it be removed? _abcoll was a private module and I didn't find dict_proxy in Python 3.2 doc.
'''

You can ignore those.  As you saw, these are undocumented and not listed in __all__.  If we ever expose these, it will likely be through the types module (or less likely through the collections.abc module which is public in 3.3).  Probably, they won't get exposed at all because they are awkward to access directly and because they have implementation specific details (i.e. other implementations have their choice of how to implement various iterators and whatnot).