During May 2025, Matthias enhanced catalog data quality for the ConductionNL/openregister repository by delivering a targeted Catalog Data Enhancements and Cleanup update. He focused on refining enumerations, adding new entries, and adjusting string values within the JSON-based dataset, while also removing and cleaning up a format URI field to improve accuracy and consistency. His approach emphasized structured data management and careful validation across the catalog, ensuring that updates were precise and well-documented through version control. Although no bugs were reported or fixed during this period, Matthias demonstrated depth in data management and JSON manipulation to elevate overall data integrity.