A horizontal bar chart displays population figures for ten countries, using a linear scale for bar lengths and a band scale for country labels. The code customizes the x-axis tick format with `d3.format` to abbreviate large numbers, converting 'G' to 'B' for billions. Data is loaded from a CSV file via `d3.csv`, and the SVG rendering uses `d3.scaleLinear`, `d3.scaleBand`, `d3.axisLeft`, and `d3.axisBottom`.