This React starter example renders a simple “Hello React!” message in a blank browser window. It imports React and ReactDOM, defines a functional `App` component returning a div, and mounts it to the root element using `ReactDOM.render`. The page loads React 16.9.0 from a CDN and runs the compiled bundle. It serves as a minimal template for building interactive visualizations with React, demonstrating the basic component structure and mounting process without any data or visual elements.