This bar chart displays the average horsepower of car models grouped by brand, with each brand represented as a vertical bar. It uses D3.js v7 to load a CSV dataset from a GitHub repository via `d3.csv`, aggregate values with `d3.rollup` and `d3.mean`, and render the visualization with `d3.scaleBand` and `d3.scaleLinear` scales. The chart includes rotated axis labels, hover effects that change bar color to orange, and explicit axis titles for Brand and Horsepower.