Allow to dispatch getting documentation on objects Base for #13860, so that object can be queried for documentation on their fields/properties. Typically this allows the following, to extend the doc documentation when requesting information on a field. In [1]: class DictLike: ...: def __getitem__(self, k): ...: if k.startswith('f'): ...: return "documentation for k" ...: else: ...: raise KeyError ...: ...: class Bar: ...: __custom_documentations__ = DictLike() ...: ...: faz = 1 ...: ...: ...: @property ...: def foo(self): ...: return 1 ...: b = Bar() In [2]: b.faz?