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="1995-107b1.jpg" />
  </query-continue>
  <query>
    <pages>
      <page pageid="4974" ns="6" title="Fil:104336.jpg" />
      <page pageid="5398" ns="6" title="Fil:12810.jpg" />
      <page pageid="5013" ns="6" title="Fil:1896 foran huset.jpg" />
      <page pageid="5190" ns="6" title="Fil:19-Sterio-Trnov.jpg" />
      <page pageid="5014" ns="6" title="Fil:1945 skelvagt.jpg" />
      <page pageid="5249" ns="6" title="Fil:1963 Ibsbo.jpg" />
      <page pageid="5255" ns="6" title="Fil:1990-121b2.jpg" />
      <page pageid="5149" ns="6" title="Fil:1990-99B6.JPG" />
      <page pageid="5383" ns="6" title="Fil:1992-98b3.jpg" />
      <page pageid="971" ns="6" title="Fil:1992 45.jpg" />
    </pages>
  </query>
</api>