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>
    <alltransclusions gatcontinue="Studiengänge" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1502" ns="10" title="Template:Blog archive" />
      <page pageid="2317" ns="10" title="Template:Britain &amp; Europe" />
      <page pageid="2593" ns="10" title="Template:Fachschaft News" />
      <page pageid="2222" ns="10" title="Template:Malory 21 Books" />
      <page pageid="3006" ns="10" title="Template:Navigation:English Didactics" />
      <page pageid="2637" ns="10" title="Template:Navigation:US Presidential Election 2008" />
      <page pageid="2545" ns="10" title="Template:Navigation Fachschaft" />
      <page pageid="1499" ns="10" title="Template:News" />
      <page pageid="2546" ns="10" title="Template:Seminarrat" />
      <page pageid="2798" ns="10" title="Template:Staff News" />
    </pages>
  </query>
</api>