This D3 v5 circle-packing visualization displays the hierarchical structure of the Flare software system, using circle size to represent the number of metrics for each module. The graph is built from a CSV file using `d3.stratify()` and `d3.pack()`, with node depth encoded through the `d3.scaleSequential(d3.interpolateMagma)` color scale. Circles are rendered as SVG elements, with clip paths and tspan text for leaf labels, while hovering highlights the ancestor chain via the `node--hover` class.