A line chart shows hourly temperature readings in San Francisco over a week, with time on the x-axis and degrees on the y-axis. The chart is rendered as an SVG using D3 v5, with scales built via `scaleTime` and `scaleLinear`, and the line path generated by `line` with `curveBasis`. Axes are added with `axisBottom` and `axisLeft`, and the data is loaded from a CSV file using `csv`.