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="Highlight|953" />
  </query-continue>
  <query>
    <pages>
      <page pageid="829" ns="0" title="Mitsubishi Galant" />
      <page pageid="864" ns="10" title="Vorlage:Highlight2" />
      <page pageid="866" ns="10" title="Vorlage:Highlight1" />
      <page pageid="868" ns="0" title="Colt CA0" />
      <page pageid="891" ns="10" title="Vorlage:Highlight3" />
      <page pageid="893" ns="10" title="Vorlage:Highlight5" />
      <page pageid="894" ns="0" title="Colt Z30 Abmessungen" />
      <page pageid="918" ns="0" title="Lancer CS0 Abmessungen" />
      <page pageid="921" ns="0" title="Lancer CY0 Abmessungen" />
      <page pageid="939" ns="0" title="Galant EA0 Abmessungen" />
    </pages>
  </query>
</api>