diff --git a/lib/utils/templatize.js b/lib/utils/templatize.js
index 859c8a2f8c..7d4ed9dd3f 100644
--- a/lib/utils/templatize.js
+++ b/lib/utils/templatize.js
@@ -360,6 +360,9 @@ function createTemplatizerClass(template, templateInfo, options) {
 }
 
 /**
+ * Adds propagate effects from the template to the template instance for
+ * properties that the host binds to the template using the `_host_` prefix.
+ * 
  * @suppress {missingProperties} class.prototype is not defined for some reason
  */
 function addPropagateEffects(template, templateInfo, options) {
@@ -423,6 +426,8 @@ function addNotifyEffects(klass, template, templateInfo, options) {
   }
   if (options.forwardHostProp && template.__dataHost) {
     for (let hprop in hostProps) {
+      // As we're iterating hostProps in this function, note whether
+      // there were any, for an optimization in addPropagateEffects
       if (!templateInfo.hasHostProps) {
         templateInfo.hasHostProps = true;
       }