diff --git a/library/composables/useMapFly.js b/library/composables/useMapFly.js
index 94d4dfe96..d75943564 100644
--- a/library/composables/useMapFly.js
+++ b/library/composables/useMapFly.js
@@ -474,8 +474,9 @@ export function useMapFly(options = {}) {
     /**
      * zoomToLegendRow — uniform "click a legend row, fit the scope it represents."
      *
-     * Reads the full `language-families` source data via map.getSource()._data
-     * and evaluates the Mapbox filter expression in JS, bypassing the viewport
+     * Reads the full `language-families` source data through readSourceFeatures()
+     * (library/maps/pin-selection.js, which knows both engines' source shapes; never
+     * the engine-private `_data` directly) and evaluates the filter expression in JS, bypassing the viewport
      * clip that previously caused off-screen regions to silently no-op. fitBounds
      * is bidirectional — it zooms OUT to a wider region just as readily as it
      * zooms IN to a tight cluster, so Africa-row and North-India-cluster-row