Worked on the valkey-io/valkey repository, focusing on refactoring expiration timestamp handling to improve code clarity and maintainability. The main contribution involved replacing raw long long types with explicit mstime_t and ustime_t typedefs throughout expiration logic, addressing ambiguity and aligning with established project conventions. This change addressed issue #2350 and laid the groundwork for a broader migration away from bare time representations, enhancing future extensibility. The work emphasized code quality and semantic precision rather than bug fixes, utilizing C programming and code refactoring skills to ensure safer, more consistent time management across modules within the software development process.