I've already mentioned this on the other thread (https://news.ycombinator.com/item?id=31569646), but my friend and I have been working on https://www.codeatlas.dev as a sideproject - it's a tool for creating pretty (2D!) visualisations of codebases, while providing additional insights via overlays (e.g. commit density, programming language or other results from static analysis like dead code/test coverage/etc.). For example here's the Kubernetes codebase visualised using codeatlas: https://www.codeatlas.dev/repo/kubernetes/kubernetes

At the moment, codeatlas is just the static gallery, but we're only a few weekends away from releasing a Github action that deploys this diagram on github pages for your own repos - if you're interested, feel free to watch this repo: https://github.com/codeatlasHQ/codebase-visualizer-action

OP, how close is this to what you had in mind in your question?

EDIT: fixed broken links :o