GeezerVison

• Remove "What's New in ..." prefixes

I see they don't show up in docs.python.org/3/whatsnew/changelog.html. Are they being removed by one of our Sphinx extensions?

Yes, see https://github.com/python/cpython/blob/HEAD/Doc/tools/extensions/misc_news.py#L33-L35 (originally introduced in python/cpython@44d0c21).

It might be that the Windows installer is ingesting the NEWS file without Sphinx processing, but perhaps it's fine to remove these prefixes anyway, because the changelog isn't the same as our carefully edited "What's New in Python" documents?

Having checked my local installations, the NEWS file is indeed included in Doc\html\NEWS. Removing the "What's New" prefixes is still likely fine here. Removing the "Python News" header is more arguable, though I would take the position that Misc/NEWS is solely for our internal consumption since splitting the actual entries to Misc/NEWS.d -- we only create the file during the process of rendering our documentation.

To the Windows point, the NEWS file would ordinarily duplicate the content in Doc\html\whatsnew\changelog.html, as the Windows builds ship the rendered documentation, but the Changelog HTML file says " The NEWS file is not available." -- we should probably aim to fix this?

Note: we currently include Misc/NEWS in the generated release archives. I do think the arguments above still hold, but worth pointing out.

https://github.com/python/release-tools/blob/master/release.py#L585-L586