Janni Wielpuetz worked on the opencast-admin-interface repository, focusing on enhancing the frontend user experience for language switching. Using React and TypeScript, Janni refactored the header component to eliminate full page reloads when changing languages, resulting in a smoother and faster workflow for administrators. The update also improved UI responsiveness by ensuring the language selection dropdown closes immediately after a change, streamlining user interactions. The work was carefully isolated to the header, minimizing risk to other parts of the application and supporting maintainability. This targeted feature addressed a specific usability issue, demonstrating thoughtful application of frontend development skills.