diff --git src/wp-includes/js/media-models.js src/wp-includes/js/media-models.js
index cba928d..854592c 100644
--- src/wp-includes/js/media-models.js
+++ src/wp-includes/js/media-models.js
@@ -65,7 +65,11 @@ window.wp = window.wp || {};
 	 */
 
 	/**
-	 * A basic comparator.
+	 * A basic equality comparator for Backbone models.
+	 *
+	 * Used to order models within a collection.
+	 *
+	 * @see wp.media.model.Attachments.comparator()
 	 *
 	 * @param  {mixed}  a  The primary parameter to compare.
 	 * @param  {mixed}  b  The primary parameter to compare.
@@ -87,7 +91,8 @@ window.wp = window.wp || {};
 		/**
 		 * media.template( id )
 		 *
-		 * Fetches a template by id.
+		 * Fetch a JavaScript template for an id, and return a templating function.
+		 *
 		 * See wp.template() in `wp-includes/js/wp-util.js`.
 		 *
 		 * @borrows wp.template as template
@@ -197,7 +202,7 @@ window.wp = window.wp || {};
 	/**
 	 * wp.media.model.Attachment
 	 *
-	 * @constructor
+	 * @class
 	 * @augments Backbone.Model
 	 */
 	Attachment = media.model.Attachment = Backbone.Model.extend({
@@ -329,7 +334,7 @@ window.wp = window.wp || {};
 		}
 	}, {
 		/**
-		 * Add a model to the end of the static 'all' collection and return it.
+		 * Create and returnAdd a model to the end of the static 'all' collection and return it.
 		 *
 		 * @static
 		 * @param {Object} attrs
@@ -339,7 +344,7 @@ window.wp = window.wp || {};
 			return Attachments.all.push( attrs );
 		},
 		/**
-		 * Retrieve a model, or add it to the end of the static 'all' collection before returning it.
+		 * Create a new model on the static 'all' attachments collection and return it.
 		 *
 		 * @static
 		 * @param {string} id A string used to identify a model.
@@ -354,8 +359,15 @@ window.wp = window.wp || {};
 	/**
 	 * wp.media.model.PostImage
 	 *
-	 * @constructor
+	 * An instance of an image that's been embedded into a post.
+	 *
+	 * Used in the embedded image attachment display settings modal (media.view.MediaFrame.ImageDetails).
+	 *
+	 * @class
 	 * @augments Backbone.Model
+	 *
+	 * @param {int} [attributes]               Initial model attributes.
+	 * @param {int} [attributes.attachment_id] ID of the attachment.
 	 **/
 	PostImage = media.model.PostImage = Backbone.Model.extend({
 
@@ -497,8 +509,20 @@ window.wp = window.wp || {};
 	/**
 	 * wp.media.model.Attachments
 	 *
-	 * @constructor
+	 * A collection of attachments.
+	 *
+	 * @class
 	 * @augments Backbone.Collection
+	 *
+	 * @param {array}  [models]                Models to initialize with the collection.
+	 * @param {object} [options]               Options object hash.
+	 * @param {string} [options.props]         Object hash for the initial query properties.
+	 * @param {string} [options.props.order]   Initial order (ASC or DESC) for the collection.
+	 * @param {string} [options.props.orderby] Initial attribute key to order the collection by.
+	 * @param {string} [options.props.query]
+	 * @param {string} [options.observe]
+	 * @param {string} [options.filters]
+	 *
 	 */
 	Attachments = media.model.Attachments = Backbone.Collection.extend({
 		/**
@@ -522,10 +546,8 @@ window.wp = window.wp || {};
 			this.props.on( 'change:orderby', this._changeOrderby, this );
 			this.props.on( 'change:query',   this._changeQuery,   this );
 
-			// Set the `props` model and fill the default property values.
 			this.props.set( _.defaults( options.props || {} ) );
 
-			// Observe another `Attachments` collection if one is provided.
 			if ( options.observe ) {
 				this.observe( options.observe );
 			}
@@ -761,6 +783,9 @@ window.wp = window.wp || {};
 			delete this.mirroring;
 		},
 		/**
+		 * If the collection is mirroring another collection, check if there are more
+		 * attachments that haven't been sync'd from the server for that collection.
+		 *
 		 * @param {Object} options
 		 * @returns {Promise}
 		 */
@@ -784,13 +809,15 @@ window.wp = window.wp || {};
 			return deferred.promise();
 		},
 		/**
-		 * @returns {Boolean}
+		 * @returns {boolean}
 		 */
 		hasMore: function() {
 			return this.mirroring ? this.mirroring.hasMore() : false;
 		},
 		/**
-		 * Overrides Backbone.Collection.parse
+		 * A custom AJAX-response parser.
+		 *
+		 * See trac ticket #24753
 		 *
 		 * @param {Object|Array} resp The raw response Object/Array.
 		 * @param {Object} xhr
@@ -867,8 +894,12 @@ window.wp = window.wp || {};
 		}
 	}, {
 		/**
+		 * A function to compare two attachment models in an attachments collection.
+		 *
+		 * Used as the default comparator for instances of wp.media.model.Attachments
+		 * and its subclasses. @see media.model.Attachments._changeOrderby().
+		 *
 		 * @static
-		 * Overrides Backbone.Collection.comparator
 		 *
 		 * @param {Backbone.Model} a
 		 * @param {Backbone.Model} b
@@ -991,22 +1022,26 @@ window.wp = window.wp || {};
 	/**
 	 * wp.media.model.Query
 	 *
-	 * A set of attachments that corresponds to a set of consecutively paged
-	 * queries on the server.
+	 * A collection of attachments that match the supplied query arguments.
 	 *
 	 * Note: Do NOT change this.args after the query has been initialized.
 	 *       Things will break.
 	 *
-	 * @constructor
+	 * @class
 	 * @augments wp.media.model.Attachments
 	 * @augments Backbone.Collection
+	 *
+	 * @param {array}  [models]                      Models to initialize with the collection.
+	 * @param {object} [options]                     Options hash.
+	 * @param {object} [options.args]                Attachments query arguments.
+	 * @param {object} [options.args.posts_per_page]
 	 */
 	Query = media.model.Query = Attachments.extend({
 		/**
 		 * @global wp.Uploader
 		 *
-		 * @param {Array} [models=[]] Array of models used to populate the collection.
-		 * @param {Object} [options={}]
+		 * @param {array}  [models=[]]  Array of models used to populate the collection.
+		 * @param {object} [options={}]
 		 */
 		initialize: function( models, options ) {
 			var allowed;
@@ -1015,6 +1050,8 @@ window.wp = window.wp || {};
 			Attachments.prototype.initialize.apply( this, arguments );
 
 			this.args     = options.args;
+			// Whether there are attachments that haven't been sync'd from the server
+			// that match the query.
 			this._hasMore = true;
 			this.created  = new Date();
 
@@ -1060,18 +1097,24 @@ window.wp = window.wp || {};
 			}
 		},
 		/**
-		 * @returns {Boolean}
+		 * Whether there are more attachments that haven't been sync'd from the server
+		 * that match the query.
+		 *
+		 * @returns {boolean}
 		 */
 		hasMore: function() {
 			return this._hasMore;
 		},
 		/**
-		 * @param {Object} [options={}]
+		 * Fetch more attachments from the server for the collection.
+		 *
+		 * @param   {object}  [options={}]
 		 * @returns {Promise}
 		 */
 		more: function( options ) {
 			var query = this;
 
+			// If there is already a request pending, return early with the Deferred object.
 			if ( this._more && 'pending' === this._more.state() ) {
 				return this._more;
 			}
@@ -1142,13 +1185,17 @@ window.wp = window.wp || {};
 		 * @readonly
 		 */
 		defaultArgs: {
-			posts_per_page: 40
+			posts_per_page: 10
 		},
 		/**
 		 * @readonly
 		 */
 		orderby: {
 			allowed:  [ 'name', 'author', 'date', 'title', 'modified', 'uploadedTo', 'id', 'post__in', 'menuOrder' ],
+			/**
+			 * Map JavaScript orderby values to their WP_Query equivalents.
+			 * @type {Object}
+			 */
 			valuemap: {
 				'id':         'ID',
 				'uploadedTo': 'parent',
@@ -1156,6 +1203,8 @@ window.wp = window.wp || {};
 			}
 		},
 		/**
+		 * A map of JavaScript query properties to their WP_Query equivalents.
+		 *
 		 * @readonly
 		 */
 		propmap: {
@@ -1262,9 +1311,9 @@ window.wp = window.wp || {};
 	/**
 	 * wp.media.model.Selection
 	 *
-	 * Used to manage a selection of attachments in the views.
+	 * A selection of attachments.
 	 *
-	 * @constructor
+	 * @class
 	 * @augments wp.media.model.Attachments
 	 * @augments Backbone.Collection
 	 */
@@ -1288,12 +1337,8 @@ window.wp = window.wp || {};
 		},
 
 		/**
-		 * Override the selection's add method.
-		 * If the workflow does not support multiple
-		 * selected attachments, reset the selection.
-		 *
-		 * Overrides Backbone.Collection.add
-		 * Overrides wp.media.model.Attachments.add
+		 * If the workflow does not support multi-select, clear out the selection
+		 * before adding a new attachment to it.
 		 *
 		 * @param {Array} models
 		 * @param {Object} options
@@ -1310,7 +1355,7 @@ window.wp = window.wp || {};
 		},
 
 		/**
-		 * Triggered when toggling (clicking on) an attachment in the modal
+		 * Fired when toggling (clicking on) an attachment in the modal.
 		 *
 		 * @param {undefined|boolean|wp.media.model.Attachment} model
 		 *
diff --git src/wp-includes/js/media-views.js src/wp-includes/js/media-views.js
index cc02f43..7111a56 100644
--- src/wp-includes/js/media-views.js
+++ src/wp-includes/js/media-views.js
@@ -2664,9 +2664,8 @@
 				state:    'insert',
 				metadata:  {}
 			});
-			/**
-			 * call 'initialize' directly on the parent class
-			 */
+
+			// Call 'initialize' directly on the parent class.
 			media.view.MediaFrame.Select.prototype.initialize.apply( this, arguments );
 			this.createIframeStates();
 
diff --git src/wp-includes/js/wp-util.js src/wp-includes/js/wp-util.js
index 867d3a0..591cd40 100644
--- src/wp-includes/js/wp-util.js
+++ src/wp-includes/js/wp-util.js
@@ -8,7 +8,7 @@ window.wp = window.wp || {};
 	/**
 	 * wp.template( id )
 	 *
-	 * Fetches a template by id.
+	 * Fetch a JavaScript template for an id, and return a templating function.
 	 *
 	 * @param  {string} id   A string that corresponds to a DOM element with an id prefixed with "tmpl-".
 	 *                       For example, "attachment" maps to "tmpl-attachment".
@@ -16,6 +16,12 @@ window.wp = window.wp || {};
 	 */
 	wp.template = _.memoize(function ( id ) {
 		var compiled,
+			/*
+			 * Underscore's default ERB-style templates are incompatible with PHP
+			 * when asp_tags is enabled, so WordPress uses Mustache-inspired templating syntax.
+			 *
+			 * @see trac ticket #22344.
+			 */
 			options = {
 				evaluate:    /<#([\s\S]+?)#>/g,
 				interpolate: /\{\{\{([\s\S]+?)\}\}\}/g,