I really like that, especially the SVG diagrams. Is this exported from some flavor of TeX?

The page source is markdown, compiled to html with pandoc using mathjax.

There's some extra pandoc filtering magic to create hoverable equations.

The svg graphs are autogenerated from markdown links inside of the pages sources.

TIL about lua filters in pandoc 2+.

I saw that there's a diagram/graphvix thing in pandoc too - is pandoc doing the svg graphs, or something else doing the autogeneration?

The svg graphs are just generated from extracting markdown links. Right now it's a bash script that writes dot code to a file, and then the dot is compiled to svg... I really need to switch that bash script to jinja or anything a little more serious.