This example shows an interactive collapsible tree diagram built with D3.js v6 in a React framework. Clicking a node toggles its children and displays a floating info panel with the node's ID, name, and value. The visualization uses SVG rendering with animated transitions via `d3.transition` and a hierarchical layout from `d3.tree`. Node and link enter/update/exit patterns handle dynamic restructuring, with `d3.select` managing the DOM and event listeners for user interaction.