Worked on the vuejs/core repository to enhance runtime stability and developer experience by addressing critical issues in function children normalization and event modifier parsing. Applied expertise in TypeScript, the DOM API, and regular expressions to update normalization logic for elements and Teleport components, ensuring correct handling of function children and accurate parsing of event modifiers such as Once, Passive, and Capture. Added comprehensive unit tests to prevent regressions and updated documentation to clarify Node.js version requirements for the SFC playground Vite Vue starter. The work emphasized robust framework development practices and improved both code reliability and onboarding clarity for contributors.