In another project we noticed the Python version mentioned in docs said 3.6+, but in reality it's 3.9+ and we'd forgotten to update that three times!

To DRY, perhaps we don't need to document this in words, seeing as we have definitive metadata inpyproject.toml?

That is:

requires-python =">=3.9"...dependencies = ["sphinx>=3.4",]

I suppose I put it in the README to make it very clear -- perhaps we could replace it with a policy statement instead? I.e.:

"It supports all Sphinx versions required by thestable Python branches."

I'm not a huge fan of this wording, though -- it feels clunky.

Well, it's okay to leave this in the README if you like, at least it's the repo's first page and not some other "hidden"/forgotten docs page.