This example demonstrates a minimal React setup where a plain-text "Hello World" message is rendered into a DOM element using vanilla JavaScript, while the React library is loaded but its rendering path remains commented out. The code also illustrates JavaScript promises, including a `waitSeconds` function that resolves after a specified delay using `setTimeout`. React 16.10.0 and ReactDOM are loaded via UMD builds from unpkg, with the page structure defined in `index.html`.