Sure. We should fix that. But the post ends with a link to the actual paper, which very much has labeled axes. Anyway, the label is "density" because it's a KD

Sure. We should fix that. But the post ends with a link to the actual paper, which very much has labeled axes. Anyway, the label is "density" because it's a KDE, which it says just above the graph: "Visualized as kernel density estimation plots (akin to smoothed histograms)". Can we get our grade back now?