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="01001.jpg" />
  </query-continue>
  <query>
    <pages>
      <page pageid="4294" ns="6" title="File:!!chinon-213-xl-01.jpg" />
      <page pageid="3882" ns="6" title="File:!Prinz-T1.jpg" />
      <page pageid="3875" ns="6" title="File:! Boots Comet Super 8b-01.jpg" />
      <page pageid="3874" ns="6" title="File:! Boots Comet Super 8c-01.jpg" />
      <page pageid="3876" ns="6" title="File:! Boots Comet Super 8d-01.jpg" />
      <page pageid="3877" ns="6" title="File:! Boots Comet Super 8e-01.jpg" />
      <page pageid="3878" ns="6" title="File:! Boots Comet Super 8f-01.jpg" />
      <page pageid="4295" ns="6" title="File:!chinon-213-xl.jpg" />
      <page pageid="4636" ns="6" title="File:01-2010 161EUR Nizo-Pro.pdf" />
      <page pageid="4637" ns="6" title="File:01-2010 178EUR Nizo-Pro.pdf" />
    </pages>
  </query>
</api>