Mention the optimised autoloader for production: "In deployment, we run composer dump-autoload --classmap-authoritative to eliminate filesystem checks."
PSR-4 maps namespace prefixes to directory paths and loads classes on demand. Classmap scans directories and builds a static map of every class. PSR-4 is standard for application code. Classmap is useful for legacy code that does not follow PSR-4 naming. In production, running composer dump-autoload --optimize generates a classmap from PSR-4 mappings for faster loading.
Fundamental PHP ecosystem knowledge. Developers who cannot explain autoloading likely have gaps in understanding dependency management and project structure.