Heinrich contributed to the matsim-libs repository by addressing a compile-time error in the PtFareConfigGroup, replacing a generic parameter set registration with a type-safe method to ensure reliable test execution and smoother CI integration. He also expanded the testing infrastructure by developing new test classes for the parking proxy module and refactored components to use MatsimRandom for reproducible results. Additionally, Heinrich introduced a utility for filtering population plans by transport mode, streamlining future refactoring efforts. His work demonstrated proficiency in Java development, refactoring, and unit testing, resulting in improved maintainability and reliability of the matsim-libs codebase.