During May 2025, Jan Hartmann focused on improving localization quality for the open-webui/open-webui repository. He addressed a UI translation issue by correcting a typo in the JSON-based localization files, ensuring that user interface text displayed accurately across supported languages. His work centered on front end development and i18n, with careful validation to confirm that the fix reduced confusion for end users and maintained consistency across locales. Although no new features were introduced, Jan prioritized release stability by refining the accuracy of localization data, demonstrating a detail-oriented approach to maintaining production quality in multilingual web applications.