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="20150513154654" timestamp="2015-05-13T15:46:54Z" ns="0" title="Spezifische Wärmekapazität" />
        <page value="20150513155730" timestamp="2015-05-13T15:57:30Z" ns="0" title="Lineare Gleichungssysteme" />
        <page value="20150513161430" timestamp="2015-05-13T16:14:30Z" ns="0" title="Hesse&#039;sche Normalenform - Aufgaben" />
        <page value="20150519102859" timestamp="2015-05-19T10:28:59Z" ns="0" title="Hesse&#039;sche Normalenform" />
        <page value="20150519205558" timestamp="2015-05-19T20:55:58Z" ns="0" title="Abstand Punkt-Gerade" />
        <page value="20150608135736" timestamp="2015-06-08T13:57:36Z" ns="0" title="Lineare Gleichungen - Aufgaben" />
        <page value="20150608144207" timestamp="2015-06-08T14:42:07Z" ns="0" title="Lineare Gleichungen" />
        <page value="20150710090813" timestamp="2015-07-10T09:08:13Z" ns="0" title="Elektrische Ladung" />
        <page value="20150710090936" timestamp="2015-07-10T09:09:36Z" ns="0" title="Elektrischer Strom" />
        <page value="20150928122227" timestamp="2015-09-28T12:22:27Z" ns="0" title="Proportionalität" />
      </results>
    </querypage>
  </query>
</api>