How does Magento\Setup\Module\Di\Code\Reader\Decorator\Area::getList() work?

Context: How does Magento\Setup\Module\Di\App\Task\Operation\Area::getDefinitionsCollection() work?

Details: How does Magento\Setup\Module\Di\Code\Reader\ClassesScanner::getList() work?

Details: How does Magento\Setup\Module\Di\Code\Reader\ClassReaderDecorator::getConstructor() work?

Result: