Carl contributed to the ExpediaGroup/xap-java-sdk repository by expanding the Car Rental API demo with new search and detail scenarios, enhancing the demo’s coverage and practical value. He implemented these features in Java, focusing on API integration and providing SDK examples that demonstrate end-to-end usage with offer tokens. Carl updated the main demo runner to incorporate the new scenarios, streamlining onboarding and testing for developers. He also revised the README to document usage patterns and scenario details, improving maintainability and clarity. The work delivered targeted, well-documented enhancements that support partners integrating the Car Rental API, reflecting a focused engineering approach.