This example demonstrates a minimal React application that renders a static "Hello World" heading. The code imports React and ReactDOM, defines a functional `App` component returning an `<h1>` element, and uses `ReactDOM.createRoot` to mount it into the `#root` div in `index.html`. It relies on the React 18 production build and a separate `bundle.js` for transpiled code, serving as a bare-bones integration of React with HTML and CSS.