The Python Devguide should explain all of this, too.

CPython Devguide > Developer Workflow > Development Cycle: https://devguide.python.org/developer-workflow/development-c...

sphinxcontrib-seqdiag works with Sphinx: http://blockdiag.com/en/seqdiag/sphinxcontrib.html#:~:text=s....

Mermaid supports Sequence Diagrams and works with GitHub: https://mermaid.js.org/syntax/sequenceDiagram.html

Digital supply chain security: https://en.wikipedia.org/wiki/Digital_supply_chain_security

SLSA Framework: Supply-chain Levels for Software Artifacts: https://github.com/slsa-framework