https://books.apple.com/us/book/mtrees-2-4-documentation-docs-design-system/id1568336630

MTREES: Modular Transnational Robust Extreme Environment System. Free first in series eBook and top "Design System" book on Apple Books. Best viewed on iPad with meticulously hand drawn illustrations. Documentation Docs is the beta, the Big Book 3.3 (currently 2.8) is nearly complete. Be gentle, its a beta!