[anticensor]

CPython is not the only Python interpreter out there.

[JeremyBanks]

The documentation sometimes suggests otherwise, but since there is no Python language specification, declaring something "part of the language" seems to have no meaning if it's not "implemented in CPython".

PyPy has had ordered dicts for longer than CPython, and Jython and IronPython don't look like they're ever going to support Python 3, so I'm not sure who this declaration is even even hypothetically relevant to.

[richardwhiuk]

It's relevant in the fact that you shouldn't rely on it as a programmer prior to this release. Changing it would have been considered a none breaking change.

[JeremyBanks]

Good point.

[earenndil]

The other major python implementation, pypy, effectively implements CPython. (And insofar as it doens't, it's heading that way.)