This multi-line chart shows the average horsepower of cars from Audi, BMW, Toyota, and Ford between 2010 and the latest available year in the dataset. It uses d3.csv to load car data from a GitHub gist, d3.rollup to group and average values by year and manufacturer, and d3.scaleLinear with d3.line to draw the series. A legend is rendered using the d3-legend plugin, while d3.axisBottom and d3.axisLeft display the time and horsepower scales on an SVG canvas.