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>
    <allfileusages gafcontinue="Bsdinstall-apache-gm.PNG|87" />
  </query-continue>
  <query>
    <pages>
      <page pageid="9" ns="0" title="Webserver mit FreeBSD® 7.2-RELEASE über Ports aufsetzen" />
      <page pageid="79" ns="0" title="FRITZ!Box7390/VoIP" />
      <page pageid="87" ns="0" title="Webserver mit FreeBSD® 9.1-RELEASE über Ports aufsetzen" />
      <page pageid="209" ns="0" title="GY-68 BMP180 Digital Barometric Pressure Sensor Module Replace BMP085 Arduino" />
      <page pageid="284" ns="0" title="Forum64 Bilder" />
    </pages>
  </query>
</api>