Kacper Oklowski focused on improving the accuracy and consistency of Opera browser compatibility data in the mdn/browser-compat-data repository. He addressed inaccuracies across CSS properties, HTML attributes, and HTTP headers by correcting data for features like box-decoration-break, speak, fieldset.disabled, and Cross-Origin-Opener-Policy. Using JSON and leveraging his expertise in browser compatibility data management, Kacper also updated internal property names to align with established naming conventions. His targeted corrections enhanced data reliability for developers, reduced confusion around Opera-specific support, and ensured changes were easily traceable. The work demonstrated careful attention to detail and a methodical approach to maintaining data quality.