Documentation of 2.x indicating what will be gone in 3.x?

[Peng Yu]

Hi,

I'm wondering if there is a document for 2.x indicating what will be
gone in 3.x. For example, I heard that __cmp__ be not available in
Python 3. But I don't see it in
http://docs.python.org/reference/datamodel.html.

Regards,
Peng