During November 2025, Hyeon worked on the zed-industries/zed repository, focusing on enhancing Rust syntax highlighting within the text editor. They implemented a feature that adds missing highlighting for the bang symbol in macro invocations, aligning the editor’s behavior with that of VS Code and improving code readability for Rust developers. Using Rust and Scheme, Hyeon addressed a gap in the syntax parsing logic, ensuring that macro invocations are visually distinct and easier to navigate. This targeted update improved the overall developer experience by reducing context-switching and making macro usage clearer, reflecting a thoughtful approach to editor feature development.