Developed Universal Module Definition (UMD) support for YouTube type definitions in the DefinitelyTyped repository, enabling seamless integration across CommonJS, AMD, and global script environments. The work involved updating TypeScript declaration files and incrementing the package version to ensure compatibility and consistency for downstream projects. Automated tests were added to validate the new UMD integration, strengthening reliability for users relying on accurate typings. This contribution demonstrated a strong understanding of module systems, type definitions, and open-source workflows, focusing on cross-environment compatibility and maintainability. The changes were merged as a production-ready pull request, reflecting careful attention to TypeScript best practices.