This example uses the D3.js v5 library to load, parse, and display a summary of the Iris dataset. The visualization fetches a CSV file, converts it to an array of objects, and uses a `flatRollup` operation with a `sum` reduction to compute the average sepal length per species, presenting the result as formatted JSON text in a `<pre>` element. The SVG and WebGL rendering in the index.html file is generated by external tools, not by the JavaScript code itself.