Worked on SVG sanitization improvements in the marimo repository, focusing on ensuring correct rendering and enhanced security for SVGs containing <defs> and <use> elements. Addressed a critical bug by updating the DOMPurify configuration in TypeScript to preserve <use> tags and their href or xlink:href attributes during the sanitization process, which mitigated XSS risks and resolved rendering issues for Matplotlib-generated SVGs. Expanded test coverage by updating and adding targeted tests in sanitize.test.ts to validate the new behavior across core rendering paths. Collaborated with other contributors, applying front end development and testing skills to deliver a robust, security-focused solution.