How should class variables be documented?

[lagru]

I'm currently dealing with the case that I want to document a class variable with numpydoc while hacking on docstub. How would I do that? Concretely

class Foo:
    """Short summary.

    Attributes
    ----------
    my_instance_var : int
    """

    my_class_var = 3

    def __init__(self):
        my_instance_var = 2

Should I add this to the existing "Attributes" section, perhaps typed with typing.ClassVar[int] or int, class variable?

@stefanv suggested that custom sections #202 might be a way to address this as well.

Apologies if I missed an existing discussion or documentation about this; I looked but didn't find one.