This example loads the Iris flower dataset from a CSV file and uses D3’s `flatRollup` and `sum` functions to compute the average sepal length for each species, displaying the result as JSON text. The visualization shows the transformed summary data in a `<pre>` element, demonstrating how to fetch, parse with `csvParse`, and aggregate data using D3 v7 within a VizHub project. It also illustrates ES6 module imports and state management through a custom `setState` pattern.