The source code

    /**
     * @class Ext.data.XmlStore
     * @extends Ext.data.Store
     * Small helper class to make creating {@link Ext.data.Store}s from XML data easier.
     * A XmlStore will be automatically configured with a {@link Ext.data.XmlReader}.
     * A store configuration would be something like:
    var store = new Ext.data.XmlStore({
        // store configs
        autoDestroy: true,
        storeId: 'myStore',
        url: 'sheldon.xml', // automatically configures a HttpProxy
        // reader configs
        record: 'Item', // records will have an "Item" tag
        idPath: 'ASIN',
        totalRecords: '@TotalResults'
        fields: [
            // set up the fields mapping into the xml doc
            // The first needs mapping, the others are very basic
            {name: 'Author', mapping: 'ItemAttributes > Author'},
            'Title', 'Manufacturer', 'ProductGroup'
        ]
    });
     *
     * This store is configured to consume a returned object of the form:
    <?xml version="1.0" encoding="UTF-8"?>
    <ItemSearchResponse xmlns="http://webservices.amazon.com/AWSECommerceService/2009-05-15">
        <Items>
            <Request>
                <IsValid>True</IsValid>
                <ItemSearchRequest>
                    <Author>Sidney Sheldon</Author>
                    <SearchIndex>Books</SearchIndex>
                </ItemSearchRequest>
            </Request>
            <TotalResults>203</TotalResults>
            <TotalPages>21</TotalPages>
            <Item>
                <ASIN>0446355453</ASIN>
                <DetailPageURL>
                    http://www.amazon.com/
                </DetailPageURL>
                <ItemAttributes>
                    <Author>Sidney Sheldon</Author>
                    <Manufacturer>Warner Books</Manufacturer>
                    <ProductGroup>Book</ProductGroup>
                    <Title>Master of the Game</Title>
                </ItemAttributes>
            </Item>
        </Items>
    </ItemSearchResponse>
     *
     * An object literal of this form could also be used as the {@link #data} config option.
     * Note: Although not listed here, this class accepts all of the configuration options of
     * {@link Ext.data.XmlReader XmlReader}.
     * @constructor
     * @param {Object} config
     * @xtype xmlstore
     */
    Ext.data.XmlStore = Ext.extend(Ext.data.Store, {
        /**
         * @cfg {Ext.data.DataReader} reader @hide
         */
        constructor: function(config){
            Ext.data.XmlStore.superclass.constructor.call(this, Ext.apply(config, {
                reader: new Ext.data.XmlReader(config)
            }));
        }
    });
    Ext.reg('xmlstore', Ext.data.XmlStore);