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="Brückentische_und_Loungelandschaft_Vogelperspektive.jpg" />
  </query-continue>
  <query>
    <pages>
      <page pageid="104" ns="6" title="File:BURAN.JPG" />
      <page pageid="194" ns="6" title="File:Badge android.png" />
      <page pageid="195" ns="6" title="File:Badge ios.png" />
      <page pageid="171" ns="6" title="File:Baum.png" />
      <page pageid="28" ns="6" title="File:Beckhoff logo red.png" />
      <page pageid="157" ns="6" title="File:Bersicht02.jpg" />
      <page pageid="156" ns="6" title="File:Bersicht07.jpg" />
      <page pageid="130" ns="6" title="File:Blank.png" />
      <page pageid="111" ns="6" title="File:Bosch logo english.png" />
      <page pageid="102" ns="6" title="File:Brückentische Vogelperspektive.jpg" />
    </pages>
  </query>
</api>