Where is the Python documentation for the special methods? (__init__, __new__, __len__, ...)

Following on from @Justin's answer, he included 95 items, here are the dunder methods I could infer: # 105 on 2.7 and 108 on 3.10:

from functools import partial
from itertools import chain


# From https://github.com/Suor/funcy/blob/0ee7ae8/funcy/funcs.py#L34-L36
def rpartial(func, *args):
    """Partially applies last arguments."""
    return lambda *a: func(*(a + args))


dunders = tuple(filter(rpartial(str.startswith, "__"),
                frozenset(chain.from_iterable((
# https://docs.python.org/3/library/stdtypes.html
                    chain.from_iterable(map(dir, (int, float, complex,
                                                  list, tuple, range,
                                                  str, bytes,
                                                  # 2.7: unicode,
                                                  bytearray, memoryview,
                                                  set, frozenset, dict, 
                                                  type, None, Ellipsis, 
                                                  NotImplemented, object)
                                            )),
# https://docs.python.org/3/library/functions.html#dir
                    dir(),
# https://docs.python.org/3/library/stdtypes.html#special-attributes
                    ("__dict__", "__class__", "__bases__", "__name__",
                     "__qualname__", "__mro__", "__subclasses__",
# https://docs.python.org/3/reference/datamodel.html#slots
                     "__slots__")
                )))))

Output on 3.10:

('__abs__',
 '__abstractmethods__',
 '__add__',
 '__alloc__',
 '__and__',
 '__annotations__',
 '__base__',
 '__bases__',
 '__basicsize__',
 '__bool__',
 '__builtins__',
 '__cached__',
 '__call__',
 '__ceil__',
 '__class__',
 '__class_getitem__',
 '__contains__',
 '__delattr__',
 '__delitem__',
 '__dict__',
 '__dictoffset__',
 '__dir__',
 '__divmod__',
 '__doc__',
 '__enter__',
 '__eq__',
 '__exit__',
 '__file__',
 '__flags__',
 '__float__',
 '__floor__',
 '__floordiv__',
 '__format__',
 '__ge__',
 '__getattribute__',
 '__getformat__',
 '__getitem__',
 '__getnewargs__',
 '__gt__',
 '__hash__',
 '__iadd__',
 '__iand__',
 '__imul__',
 '__index__',
 '__init__',
 '__init_subclass__',
 '__instancecheck__',
 '__int__',
 '__invert__',
 '__ior__',
 '__isub__',
 '__itemsize__',
 '__iter__',
 '__ixor__',
 '__le__',
 '__len__',
 '__loader__',
 '__lshift__',
 '__lt__',
 '__mod__',
 '__module__',
 '__mro__',
 '__mul__',
 '__name__',
 '__ne__',
 '__neg__',
 '__new__',
 '__or__',
 '__package__',
 '__pos__',
 '__pow__',
 '__prepare__',
 '__qualname__',
 '__radd__',
 '__rand__',
 '__rdivmod__',
 '__reduce__',
 '__reduce_ex__',
 '__repr__',
 '__reversed__',
 '__rfloordiv__',
 '__rlshift__',
 '__rmod__',
 '__rmul__',
 '__ror__',
 '__round__',
 '__rpow__',
 '__rrshift__',
 '__rshift__',
 '__rsub__',
 '__rtruediv__',
 '__rxor__',
 '__set_format__',
 '__setattr__',
 '__setitem__',
 '__sizeof__',
 '__slots__',
 '__spec__',
 '__str__',
 '__sub__',
 '__subclasscheck__',
 '__subclasses__',
 '__subclasshook__',
 '__text_signature__',
 '__truediv__',
 '__trunc__',
 '__weakrefoffset__',
 '__xor__')