The note from the python-dev discussion can just be added here as a second paragraph:

Note that when adopting this theme, you're also borrowing an element of the trust and credibility established by the CPython core developers over the years. That's fine, and you're welcome to do so for other Python community projects if you so choose, but please keep in mind that in doing so you're also choosing to accept some of the responsibility for maintaining that collective trust.

Done, thank you. :)

Are we planning to support installing this theme for use in Py2 docs builds? If not, we can just use the open() builtin directly here, rather than going through the io module.

Although this is technically for the Python 3 docs, using io.open over open is pretty cheap for us, especially considering this package contains almost no Python code. :)