This horizontal bar chart displays the populations of 20 countries in 2020, ordered by country name along the vertical axis with population values extending horizontally. Each bar includes a tooltip showing the population in billions. The visualization is built with React and D3 v5, using `d3.scaleBand` for the categorical y-axis, `d3.scaleLinear` for the numeric x-axis, and `d3.format` to convert raw values into abbreviated population labels. Data is loaded from a remote CSV file via `d3.csv`, and the chart is rendered as SVG with custom axis and mark components.