This fork of Curran Kelleher’s radial tree visualizes a hierarchy of world countries, grouped by continent and subregion, with labels placed along circular branches. Users can pan and zoom the entire SVG scene using `d3.zoom` and `d3.event.transform`. The code builds the layout with `d3.cluster` and `d3.hierarchy`, projects nodes via a custom `project` function, and sizes text with `d3.scaleSqrt` based on depth. The underlying data is loaded from `data.json` using `d3.json`.