Q16: I'm trying to customize

setup.py

generation by following https://www.pantsbuild.org/docs/plugins-setup-py. It turns out working pretty-well: https://github.com/lablup/backend.ai/blob/751fb751ebaced53467c33e62546465e8902a77a/tools/pants-plugins/setupgen/register.py Are there any references/docs about pants' internal engine APIs?

Other than what's on the pantsbuild docs site, I don't think there's much else for dev docs. The landscape changes quickly, so that's part of the reason why. Feel free to grok other pieces of code for more understanding, and when you're stuck ask in #development or #plugins

Thanks for the pointers!