This example displays summary statistics from the classic Iris flower dataset. After loading the data with `d3.csvParse`, it computes the average sepal length for each species using `d3.flatRollup` and `d3.sum`, then renders the resulting JSON object as text in a `<pre>` element via a D3 data join. The visualization demonstrates importing D3 modules locally, fetching data with `fetch`, and managing asynchronous state updates through a simple state management pattern. It also showcases loading D3 v7 from UNPKG and composing modular ES6 JavaScript files.