Ezio's comment got me to reread the entire paragraph. I do not like it. 'Having you think' is wrong; 'Basically just' is unneeded; 'guaranteed' is hyperbole; and the paragraph is otherwise repetitive, vague, and pretty useless. For most issues "the core developer who eventually handles your patch will make the final call on whether something is acceptable" is not exactly true and misses the point that we have clearly defined policies that all core developers follow. Here is a suggested replacement that says what is actually acceptable for what versions.

"Second, follow our backwards-compatibility and upgrade policies. New parameters (whose default is the current behavior), functions, and methods may be accepted, but only for a future x.y version. New classes, modules, and syntax (including keywords) get increasingly severe scrutiny and require discussion on the python-dev list. Bug fixes that make behavior better match the documented intention are nearly always accepted for current releases. So are fixes for mistakes and sufficiently bad wording in the documents. Changes away from the current documented behavior are only occasionally accepted and only for future releases. Since they nearly always require at least a few people to update their code, they require special consideration, including a python-dev discussion, and a deprecation process."