This is a simple D3 "graph" (a hierarchy tree, really) of the most popular websites. I wanted to scan the top 1 milllion websites, but my PC had a mandatory update; so it restarted over the weekend. And 60k-ish domains took a few days.
It's a .net core CLI application, should work out of the box.
The blog article on https://michaelhendrickx.com/201911-certgraph:-visualizing-the-distribution-of-trusted-ca's.html will give some background on this.
For any questions, contact me on firstname.lastname@example.org