This multi-series line chart visualizes how average credit amount, age, and installment commitment vary with loan duration, using normalized values to compare three metrics on a single axis. The D3.js v7 code loads a CSV dataset from a GitHub gist, aggregates records by duration, and applies min-max scaling to each series. Three separate line paths, colored blue, green, and an additional series, are drawn using d3.line and d3.scaleLinear, with axes generated via d3.axisBottom and d3.axisLeft. The chart renders as an SVG, with data aggregation performed through d3.rollups and d3.mean.