Full code after the jump.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/08/22/determining-the-xml-classs-settings-in-actionscript-30/ -->
<mx:Application name="XML_settings_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            import mx.utils.ObjectUtil;

            private function init():void {
                var obj:Object = XML.settings();
                textArea.text = ObjectUtil.toString(obj);
            }
        ]]>
    </mx:Script>

    <mx:TextArea id="textArea"
            editable="false"
            width="100%"
            height="100%"
            creationComplete="init();" />

    <mx:Label text="{Capabilities.version}" />

</mx:Application>

View source is enabled in the following example.

For more information on the XML class’s settings() method, see the Flex 3 documentation at http://livedocs.adobe.com/flex/3/langref/XML.html#settings().