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="Aa3_shantytown_scenic_pic.png" />
  </query-continue>
  <query>
    <pages>
      <page pageid="27" ns="6" title="File:7.34-sitrep.jpg" />
      <page pageid="28" ns="6" title="File:7.51-training.png" />
      <page pageid="1152" ns="6" title="File:AKS-74U.jpg" />
      <page pageid="1136" ns="6" title="File:AT4.jpg" />
      <page pageid="1100" ns="6" title="File:Aa3 airfield scenic pic.png" />
      <page pageid="1101" ns="6" title="File:Aa3 alley scenic pic.png" />
      <page pageid="1102" ns="6" title="File:Aa3 bridge scenic pic.png" />
      <page pageid="1103" ns="6" title="File:Aa3 impact scenic pic.png" />
      <page pageid="1104" ns="6" title="File:Aa3 pipeline scenic pic.png" />
      <page pageid="1105" ns="6" title="File:Aa3 ranch scenic pic.png" />
    </pages>
  </query>
</api>