diff --git a/src/ol/interaction/keyboardzoominteraction.js b/src/ol/interaction/keyboardzoominteraction.js
index 2bb807e138..7965fd0aa2 100644
--- a/src/ol/interaction/keyboardzoominteraction.js
+++ b/src/ol/interaction/keyboardzoominteraction.js
@@ -57,6 +57,9 @@ goog.inherits(ol.interaction.KeyboardZoom, ol.interaction.Interaction);
 
 
 /**
+ * Handles the {@link ol.MapBrowserEvent map browser event} if it was a
+ * `KeyEvent`, and decides whether to zoom in or out (depending on whether the
+ * key pressed was '+' or '-').
  * @param {ol.MapBrowserEvent} mapBrowserEvent Map browser event.
  * @return {boolean} `false` to stop event propagation.
  * @this {ol.interaction.KeyboardZoom}