You are looking at the HTML representation of the XML format.
HTML is good for debugging, but probably is not suitable for your application.
See complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query-continue>
    <allimages gaifrom="540 DownloadFiles.jpg" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1239" ns="6" title="File:540 AddGroupsBlank.jpg" />
      <page pageid="1241" ns="6" title="File:540 AddGroupsFilterCrop.jpg" />
      <page pageid="1240" ns="6" title="File:540 AddGroupsListCrop.jpg" />
      <page pageid="1139" ns="6" title="File:540 AutoRAR.jpg" />
      <page pageid="1143" ns="6" title="File:540 AutoRAROptions.jpg" />
      <page pageid="1141" ns="6" title="File:540 AutoRARProperties.jpg" />
      <page pageid="1142" ns="6" title="File:540 AutoRARRightClick.jpg" />
      <page pageid="1140" ns="6" title="File:540 AutoRARToolbar.jpg" />
      <page pageid="1229" ns="6" title="File:540 BigToolbar.jpg" />
      <page pageid="1230" ns="6" title="File:540 ButtonToolbar.jpg" />
    </pages>
  </query>
</api>