A sample React app displays a static “Hello World” message inside a preformatted HTML element. The interface shows the text in large, monospaced type on a blank page, with no interactive behavior. The implementation consists of an `index.html` file that references a bundled JavaScript file, and an `index.js` module that uses `document.getElementById` to directly update the text content of the message element. This minimal example demonstrates the basic structure of a React starter project, though it relies on vanilla DOM manipulation rather than React components or state. The data source is a single hardcoded JavaScript string.