A React application renders an SVG circle that follows the mouse cursor across a 960 by 500 pixel canvas. The circle's position updates in real-time via React state and the `onMouseMove` event handler, reading the cursor's `clientX` and `clientY` coordinates. When the mouse leaves the SVG area, the circle returns to its initial centered position through the `onMouseLeave` handler. React 16.9's `useState` and `useCallback` hooks manage the state updates efficiently.