Worked on the marimo-team/marimo repository to enhance the frontend data table by addressing locale-aware number formatting issues. Focused on preventing unintended rounding of raw numeric data, the developer refactored the formatting logic using React and TypeScript, introducing a centralized LocaleNumber workflow and updating related utilities. Comprehensive tests were added to cover multiple locales such as en-US, de-DE, fr-FR, and ja-JP, as well as edge cases including large and small numbers, negatives, and special values. These improvements reduced the risk of numeric misinterpretation across regions and strengthened the codebase’s readiness for global deployment and ongoing maintainability.