Currently, there's no obvious indication when viewing the Python Packaging User Guide itself that it's an officially blessed project of not only the pip/virtualenv/pypi/twine/setuptools development teams, but also of the CPython core developers. The "packaging.python.org" URL isn't enough, especially when the ReadTheDocs link is still better known to search engines.

It would be desirable to align the theming of the Packaging User Guide with that of the main documentation to help make that connection clearer to readers.
The current docs theme components: http://hg.python.org/cpython/file/default/Doc/tools/sphinxext/

(Also see #304 for discussion of the considerations of theme switching in general)