This bar chart displays the population of the top 10 most populous countries in 2018, based on United Nations data. It uses a linear x-scale for population and a banded y-scale for country names. The code employs D3 v5’s `scaleLinear`, `scaleBand`, `axisLeft`, and `axisBottom` APIs to render axes, with tick labels formatted using `format(".3s")` and a custom replacement of 'G' with 'B' for billions. Grid lines are drawn via `tickSize(-innerHeight)`, and the chart is rendered as SVG.