diff --git a/lib/mixins/property-accessors.html b/lib/mixins/property-accessors.html
index 90e521ff3b..030f32ec67 100644
--- a/lib/mixins/property-accessors.html
+++ b/lib/mixins/property-accessors.html
@@ -96,6 +96,7 @@
     /**
      * @polymerMixinClass
      * @implements {Polymer_PropertyAccessors}
+     * @extends HTMLElement
      * @unrestricted
      */
     class PropertyAccessors extends superClass {
@@ -120,6 +121,14 @@
         this._initializeProperties();
       }
 
+      /**
+       * Implements native Custom Elements `attributeChangedCallback` to
+       * set an attribute value to a property via `_attributeToProperty`.
+       *
+       * @param {string} name Name of attribute that changed
+       * @param {?string} old Old attribute value
+       * @param {?string} value New attribute value
+       */
       attributeChangedCallback(name, old, value) {
         if (old !== value) {
           this._attributeToProperty(name, value);
@@ -214,8 +223,8 @@
        * a typed value.
        *
        * @param {string} attribute Name of attribute to deserialize.
-       * @param {string} value of the attribute.
-       * @param {*} type type to deserialize to.
+       * @param {?string} value of the attribute.
+       * @param {*=} type type to deserialize to.
        */
       _attributeToProperty(attribute, value, type) {
         // Don't deserialize back to property if currently reflecting
@@ -306,8 +315,8 @@
        * Note: The return value of `undefined` is used as a sentinel value to
        * indicate the attribute should be removed.
        *
-       * @param {string} value Attribute value to deserialize.
-       * @param {*} type Type to deserialize the string to.
+       * @param {?string} value Attribute value to deserialize.
+       * @param {*=} type Type to deserialize the string to.
        * @return {*} Typed value deserialized from the provided string.
        */
       _deserializeValue(value, type) {
@@ -326,7 +335,7 @@
 
           case Object:
             try {
-              outValue = JSON.parse(value);
+              outValue = JSON.parse(/** @type string */(value));
             } catch(x) {
               // allow non-JSON literals like Strings and Numbers
             }
@@ -334,7 +343,7 @@
 
           case Array:
             try {
-              outValue = JSON.parse(value);
+              outValue = JSON.parse(/** @type string */(value));
             } catch(x) {
               outValue = null;
               console.warn(`Polymer::Attributes: couldn't decode Array as JSON: ${value}`);
@@ -427,7 +436,8 @@
        */
       _setPendingProperty(property, value) {
         let old = this.__data[property];
-        if (this._shouldPropertyChange(property, value, old)) {
+        let changed = this._shouldPropertyChange(property, value, old)
+        if (changed) {
           if (!this.__dataPending) {
             this.__dataPending = {};
             this.__dataOld = {};
@@ -438,8 +448,8 @@
           }
           this.__data[property] = value;
           this.__dataPending[property] = value;
-          return true;
         }
+        return changed;
       }
 
       /**
diff --git a/lib/utils/boot.html b/lib/utils/boot.html
index 0a15f5ed1d..6f5d993530 100644
--- a/lib/utils/boot.html
+++ b/lib/utils/boot.html
@@ -16,14 +16,14 @@
   /**
    * @namespace Polymer
    * @summary Polymer is a lightweight library built on top of the web
-   * standards-based Web Components API's, and makes it easy to build your
-   * own custom HTML elements.
+   *   standards-based Web Components API's, and makes it easy to build your
+   *   own custom HTML elements.
    * @param {Object} info Prototype for the custom element. It must contain
-   * an `is` property to specify the element name. Other properties populate
-   * the element prototype. The `properties`, `observers`, `hostAttributes`,
-   * and `listeners` properties are processed to create element features.
+   *   an `is` property to specify the element name. Other properties populate
+   *   the element prototype. The `properties`, `observers`, `hostAttributes`,
+   *   and `listeners` properties are processed to create element features.
    * @return {Object} Returns a custom element class for the given provided
-   * prototype `info` object. The name of the element if given by `info.is`.
+   *   prototype `info` object. The name of the element if given by `info.is`.
    */
   window.Polymer = function(info) {
     return window.Polymer._polymerFn(info);
@@ -35,15 +35,20 @@
   }
 
   // To be plugged by legacy implementation if loaded
+  /* eslint-disable valid-jsdoc */
   /**
    * @param {Object} info Prototype for the custom element. It must contain
-   * an `is` property to specify the element name. Other properties populate
-   * the element prototype. The `properties`, `observers`, `hostAttributes`,
-   * and `listeners` properties are processed to create element features.
+   *   an `is` property to specify the element name. Other properties populate
+   *   the element prototype. The `properties`, `observers`, `hostAttributes`,
+   *   and `listeners` properties are processed to create element features.
+   * @return {Object} Returns a custom element class for the given provided
+   *   prototype `info` object. The name of the element if given by `info.is`.
    */
   window.Polymer._polymerFn = function(info) { // eslint-disable-line no-unused-vars
     throw new Error('Load polymer.html to use the Polymer() function.');
   }
+  /* eslint-enable */
+
   window.Polymer.version = '2.0.0';
 
   /* eslint-disable no-unused-vars */