React DevTools is a crucial open-source tool developed by Meta, designed to enhance debugging capabilities for React projects within browser DevTools, and it is available both as a browser extension and a standalone package for non-browser applications like React Native. The tool, which can be installed from popular web browsers' add-on stores or built from the source, offers features such as a performance debugging tool called the React Profiler, themable environments, and the ability to access React components and state directly from the console. Furthermore, React DevTools supports interaction tracking through a programmatic API, allowing developers to label and trace events for improved performance analysis. Since its v4 release in 2019, React DevTools has been continuously updated, introducing enhancements such as support for older React versions, a simplified tree view, improved tooltips, and the ability to search the timeline by component name, all while maintaining a focus on performance and user experience. Brian Vaughn, a key developer of React DevTools, has significantly contributed to its development, providing resources like talks and podcasts to help developers master its use.