A correlation diagram displays relationships between nodes as a series of curved arcs, with nodes positioned along a horizontal axis and links drawn as arcs above them. The visualization highlights connections on mouseover by adjusting opacity, stroke width, and label size. Built with React and D3 v7, the code uses `arcDiagram` for layout, `scalePoint` for node positioning, and SVG `path` elements with elliptical arc commands. Data is loaded as JSON from a GitHub gist and rendered as circles with rotated text labels.