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="Chuck_Davies|333" />
  </query-continue>
  <query>
    <pages>
      <page pageid="12" ns="0" title="Portada" />
      <page pageid="241" ns="0" title="Subasta de caridad" />
      <page pageid="331" ns="0" title="Charles Davies" />
      <page pageid="526" ns="0" title="Bo-Gilliam" />
      <page pageid="539" ns="0" title="Big Blue Fox" />
      <page pageid="540" ns="0" title="BBF" />
      <page pageid="553" ns="0" title="Callejón de Artistas" />
      <page pageid="645" ns="0" title="Caricaturista" />
      <page pageid="1103" ns="0" title="Bob buffalo" />
      <page pageid="1521" ns="0" title="CEBRA" />
    </pages>
  </query>
</api>