Worked on the hapifhir/hapi-fhir repository, focusing on backend enhancements for bulk export workflows. Addressed a critical data integrity issue by updating history export logic to use persistent IDs instead of client-assigned string IDs, ensuring complete and accurate export histories when _includeHistory was enabled. Later, implemented a tri-state parameter for expandMdm in bulk export, allowing the system to distinguish between true, false, and null values for more robust default handling. These contributions involved Java, Spring, and API development, with careful attention to changelog updates, documentation, and code review feedback to maintain consistency and reliability across export operations.