diff --git a/lighthouse-treemap/app/src/main.js b/lighthouse-treemap/app/src/main.js
index 5a7449154054..60c173c20c95 100644
--- a/lighthouse-treemap/app/src/main.js
+++ b/lighthouse-treemap/app/src/main.js
@@ -612,7 +612,7 @@ class TreemapViewer {
 
       dom.style.backgroundColor = depthOneNodeColor;
 
-      // Set a bicolor background to communicate unused-bytes
+      // Shade the element to communicate coverage.
       if (this.currentViewMode.id === 'unused-bytes') {
         const pctUsed = (1 - (node.unusedBytes || 0) / node.resourceBytes) * 100;
         dom.style.setProperty('--pctUsed', `${pctUsed}%`);