You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query-continue>
    <querypage qpoffset="10" />
  </query-continue>
  <query>
    <querypage name="Ancientpages">
      <results>
        <page value="20090320101123" timestamp="2009-03-20T10:11:23Z" ns="0" title="Genereller Aufbau" />
        <page value="20090321141452" timestamp="2009-03-21T14:14:52Z" ns="0" title="Video Die Installation auf dem Webserver" />
        <page value="20090321151234" timestamp="2009-03-21T15:12:34Z" ns="0" title="Video Einbau einer Artikelliste" />
        <page value="20090321164834" timestamp="2009-03-21T16:48:34Z" ns="0" title="Video Volldynamische Website - Der CSS-Aufbau" />
        <page value="20090323105823" timestamp="2009-03-23T10:58:23Z" ns="0" title="Newsletter-Modul" />
        <page value="20090323162801" timestamp="2009-03-23T16:28:01Z" ns="0" title="Guide Bedienung des Backends" />
        <page value="20090324145104" timestamp="2009-03-24T14:51:04Z" ns="0" title="Kalender-Modul" />
        <page value="20090526115922" timestamp="2009-05-26T11:59:22Z" ns="0" title="XML-Schnittstelle in Modulen" />
        <page value="20090807155300" timestamp="2009-08-07T15:53:00Z" ns="0" title="Template-Engine" />
        <page value="20090928123903" timestamp="2009-09-28T12:39:03Z" ns="0" title="Forum-Modul" />
      </results>
    </querypage>
  </query>
</api>