setuptools
Domain: Python Packaging
🎯 Motivation
The most widely used build backend. It evolved from distutils and handles package discovery, metadata, and building wheels/sdists.
📋 Concrete Example
Add requires = ["setuptools"] to [build-system], then setuptools finds your packages with find: or find_namespace:.
🔗 Analogy
setuptools is the Swiss Army knife of packaging — old, bulky, but it has a tool for nearly every job.