Manuel contributed targeted bug fixes to the php/php-src repository, focusing on core memory management in PHP. Over two months, he addressed issues where memory_limit enforcement did not properly respect max_memory_limit, ensuring user-defined limits could not bypass system constraints. Using C and PHP, Manuel implemented changes that improved the reliability and predictability of memory allocation, particularly under edge cases and high-load scenarios. His work included adding regression tests to validate memory management behavior and updating initialization logic for memory limits. These contributions demonstrated depth in backend development, debugging, and memory management, resulting in more stable and maintainable PHP core behavior.