`ndarray.base` seems like it would be useful state for implementers of `__array_finalize__`: ```python In [1]: class bad(np.ndarray): ...: def __array_finalize__(self, x): ...: print("Base is", self.base) ...: In [2]: x = np.array(1).view(bad) Base is None In [3]: x.base Out[3]: array(1) ```