The chart shows 15 years of car sales using a combined line and area chart. A black line traces sales over time, while a grey filled area beneath it emphasizes the trend, with axes labeled "Sales" and "Year." It uses D3 v5 APIs including `scaleTime`, `scaleLinear`, `axisBottom`, `axisLeft`, `line`, and `area` with `curveBasis` for smoothing. The SVG rendering loads CSV data from a remote gist, parses dates, and formats the y-axis tick labels with `format('.3s')`.