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 garcontinue="Using_a_levelgen_script|25" />
  </query-continue>
  <query>
    <pages>
      <page pageid="10" ns="0" title="How to build Bitfighter" />
      <page pageid="40" ns="0" title="Creating levels" />
      <page pageid="48" ns="0" title="Levelgen gallery funcorners" />
      <page pageid="49" ns="0" title="Levelgen Gallery: Funcorners" />
      <page pageid="55" ns="0" title="Hosting a dedicated server on windows" />
      <page pageid="56" ns="0" title="Making a mac server" />
      <page pageid="69" ns="0" title="Making a Mac server" />
      <page pageid="90" ns="0" title="Script Structure" />
      <page pageid="96" ns="0" title="Running Buglist" />
      <page pageid="130" ns="0" title="Level Design Tips" />
    </pages>
  </query>
</api>