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>
    <exturlusage>
      <eu pageid="197" ns="4" title="Proyecto Krahe:Acerca de" url="http://www.mediawiki.org" />
      <eu pageid="1" ns="0" title="Página Principal" url="http://www.mediawiki.org" />
      <eu pageid="258" ns="274" title="Widget:Facebook Like Box" url="http://www.mediawiki.org/wiki/Extension:Widgets" />
      <eu pageid="260" ns="274" title="Widget:YouTube" url="http://www.mediawiki.org/wiki/Extension:Widgets" />
      <eu pageid="261" ns="274" title="Widget:Twitter" url="http://www.mediawiki.org/wiki/Extension:Widgets" />
      <eu pageid="202" ns="12" title="Ayuda:Cómo se edita una página" url="http://www.mediawiki.org/wiki/Help:Contents" />
    </exturlusage>
  </query>
</api>