diff --git a/lib/utils/mixin.html b/lib/utils/mixin.html
index 525d1bc209..dd7936b9c2 100644
--- a/lib/utils/mixin.html
+++ b/lib/utils/mixin.html
@@ -38,6 +38,7 @@
    * @memberof Polymer
    * @template T
    * @param {T} mixin ES6 class expression mixin to wrap
+   * @return {T}
    * @suppress {invalidCasts}
    */
   Polymer.dedupingMixin = function(mixin) {
diff --git a/lib/utils/templatize.html b/lib/utils/templatize.html
index c4290724e2..28810322f1 100644
--- a/lib/utils/templatize.html
+++ b/lib/utils/templatize.html
@@ -257,6 +257,7 @@
       /**
        * @constructor
        * @extends {base}
+       * @private
        */
       let klass = class extends base { };
       klass.prototype.__templatizeOptions = options;
@@ -464,6 +465,7 @@
         // Host property forwarding must be installed onto template instance
         addPropagateEffects(template, templateInfo, options);
         // Subclass base class and add reference for this specific template
+        /** @private */
         let klass = class TemplateInstance extends baseClass {};
         klass.prototype._methodHost = findMethodHost(template);
         klass.prototype.__dataHost = template;