Backbone.Collection.fetch() response headers

HTML

<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/underscore.js/1.5.2/underscore-min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/backbone.js/1.1.0/backbone-min.js"></script>
<div>
    <button type="button" id="fetch-btn">Fetch Collection</button>
</div>

<div>
    <textarea rows="10" cols="40" id="results"></textarea>
</div>

JavaScript

$(function() {
    var Model = Backbone.Model.extend({});

    var Collection = Backbone.Collection.extend({
        url: 'https://api.github.com/users/jashkenas/repos',
        model: Model,

        fetch: function(options) {
            var jqXHR = Backbone.Collection.prototype.fetch.call(this, options);
            jqXHR.done(function() {
                $('#results').val(jqXHR.getAllResponseHeaders());
            });
            return jqXHR;
        }
    });

    var collection = new Collection();

    $('#fetch-btn').click(function() {
        collection.fetch();
    });
});