This heatmap visualizes the frequency of TODO comments across code files, with each cell colored by intensity on a dark background. The visualization uses D3 v5’s `d3.scaleSequential` for color mapping and `d3.select` with SVG rect elements to construct the grid. Data is precomputed and rendered as a static matrix, with axis labels omitted. The page loads D3 from a CDN and applies a minimalist CSS reset, focusing entirely on the density pattern of coding tasks. The SVG canvas is 960 by 500 pixels, and the visualization reads from a bundled JavaScript file.