This example displays the text “Hello React!” centered on the page, serving as a minimal demonstration of React rendering. It uses React 16.10.0 and ReactDOM to mount a functional component into a `div#root` element, with styling applied through a CSS class. The code imports `React` and `ReactDOM` directly and calls `ReactDOM.render` to display the component, relying on the production builds of React and ReactDOM loaded via CDN links in the HTML file.