Worked on the facebook/buck2 repository to enhance enum usability by implementing attribute-based enum value access, allowing developers to reference values using the Color.RED syntax instead of the previous function-call approach. This change improved code readability and ergonomics while maintaining backward compatibility, as the original Color("RED") syntax remained supported to minimize migration friction for existing users. The work involved careful language design and enum implementation using Rust and Starlark, ensuring API stability and laying the groundwork for future enhancements. The update aimed to streamline onboarding for contributors and facilitate easier future extensions to enum handling within the Buck2 codebase.