Mridul contributed to the mrdoob/three.js repository by modernizing core utilities and stabilizing the 3D rendering pipeline. He refactored internal JavaScript code, replacing deprecated methods with safer alternatives such as slice and Array.isArray, and updated the List class to generate IDs using modern techniques. These changes improved code maintainability and compatibility, reducing the risk of runtime errors. Additionally, Mridul fixed a validation issue in the Vector4 rendering path, ensuring proper uniform handling in WebGL-based rendering. His work demonstrated a solid understanding of JavaScript, Node.js, and 3D rendering, focusing on long-term code safety and collaborative development practices.