OT: I thought the docs for pyre-check.org looked really nice. Didn't look like a Jekyll or Sphinx template. Looked at the source code and it's another FB library, Docusaurus, which uses React and Markdown:
https://docusaurus.io/Had been briefly discussed a few months ago on HN [0] but I guess I missed it. Always looking for some variety in static site/docs deployment!
[0] https://news.ycombinator.com/item?id=15924779