During March 2025, Caspar Kielwein focused on enhancing code quality and maintainability in the TheGiraffe3/endless-sky repository. He implemented a comprehensive refactor to enforce const correctness throughout the C++ codebase, systematically marking parameters and member functions as const where appropriate. This approach reduced the risk of unintended mutations, improved code safety, and made future refactoring efforts more straightforward. By prioritizing const correctness and careful refactoring, Caspar enabled safer changes and allowed for better compiler optimizations. His work laid a solid foundation for more robust engine behavior, demonstrating depth in C++ development and a strong commitment to maintainable software design.