Bryan Richter via ghc-devs
A quick googling discovered https://githubnext.com/projects/repo-visualization, which has some of the desired features. :)
Another somewhat-related visualiation tool that can produce some pretty pictures is gource [1]. I wouldn't call the output "useful" per se, but it is mildly amusing to see the avatars frenetically flying about the source tree. It gives you a sense of just how many people are responsible for building the GHC that we know and love. Here [2] is a rendering of ghc's history. Best to skip the first minute or so, which is largely just Will Partain setting things up. Things really start to pick up around 2012 (around the 6 minute mark); it's truly dizzying. Happily, this momentum has persisted to this day. Cheers, - Ben [1] https://gource.io/ [2] http://home.smart-cactus.org/~ben/ghc/gource-2022-06-14.mkv