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>
    <allimages gaicontinue="20091223_05_start_spiraal.jpg" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1116" ns="6" title="Bestand:(S)LWR Normale platte wagens op vaste assen.jpg" />
      <page pageid="1221" ns="6" title="Bestand:002.jpg" />
      <page pageid="1390" ns="6" title="Bestand:03-04-2009 Utg Shimmns-ttu.JPG" />
      <page pageid="1391" ns="6" title="Bestand:03-04-2014 Utg Shimmns-u DB.jpg" />
      <page pageid="673" ns="6" title="Bestand:20091218 halfhout verbindingen.jpg" />
      <page pageid="672" ns="6" title="Bestand:20091218 zo moet het.jpg" />
      <page pageid="674" ns="6" title="Bestand:20091220 frame in elkaar geschroefd.jpg" />
      <page pageid="676" ns="6" title="Bestand:20091222 06 allemaal in delen.jpg" />
      <page pageid="677" ns="6" title="Bestand:20091222 08 detail.jpg" />
      <page pageid="675" ns="6" title="Bestand:20091222 tafelframe.jpg" />
    </pages>
  </query>
</api>