A horizontal tree visualization displays hierarchical data as a branching layout flowing left to right. Each root node represents a separate dataset, with nested child nodes indicating control-state relationships and timing information. The visualization uses D3 v5’s tree layout, `linkHorizontal` path generator, and SVG rendering to draw the structure. Hovering over any node displays a breadcrumb trail at the bottom, showing the full path from root to that node, built from the data’s CT property.