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>
    <allredirects arcontinue="Using_a_levelgen_script" />
  </query-continue>
  <query>
    <allredirects>
      <r ns="0" title="Building Bitfighter" />
      <r ns="0" title="Hosting a Dedicated Server in OS X" />
      <r ns="0" title="Hosting a dedicated server on Windows" />
      <r ns="0" title="Level file syntax" />
      <r ns="0" title="Levelgen Gallery: Funcorners" />
      <r ns="0" title="Levelgen example: Funcorners" />
      <r ns="0" title="Making a Mac server" />
      <r ns="0" title="Running Bug List" />
      <r ns="0" title="Script structure" />
      <r ns="0" title="Three Keys of Level Design" />
    </allredirects>
  </query>
</api>