This example displays a treemap visualization of hierarchical data, with the current view showing video game sales grouped by platform, or movie and Kickstarter data sets selectable via links at the top. It uses the d3 v4 API, specifically `d3.treemap()`, `d3.hierarchy()`, and `d3.scaleOrdinal` with the `schemeCategory20` color palette, to render the nested rectangles. The SVG output includes tooltips on mouseover, which display the name, category, and value of each tile using data attributes.