Thank you! Until a few years ago, this project ran on PHP. It was then later rewritten in Common Lisp. I published the Common Lisp source code for this website only about a week ago. That's why I thought of making this "Show HN" post today.

Until now, the source code published on GitHub has usually been a few versions behind the live website running at https://mathb.in/ but I am hoping that in future, I will keep the source code on GitHub as recent and as updated as possible.