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="Headertabs|57" />
  </query-continue>
  <query>
    <pages>
      <page pageid="3" ns="0" title="Hercules Prima 5 S" />
      <page pageid="8" ns="0" title="Hercules Prima GT" />
      <page pageid="13" ns="0" title="Sachs MadAss 50" />
      <page pageid="32" ns="0" title="Aprilia RS 50 Extrema" />
      <page pageid="33" ns="0" title="Zündapp ZA 25" />
      <page pageid="34" ns="0" title="Zündapp ZA 40" />
      <page pageid="35" ns="0" title="Gilera GSM 50" />
      <page pageid="946" ns="6" title="Datei:MK1.jpg" />
      <page pageid="984" ns="6" title="Datei:K125BW V2.jpg" />
      <page pageid="986" ns="6" title="Datei:K125BW v1.jpg" />
    </pages>
  </query>
</api>