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>
    <allfileusages gafcontinue="Building_Fountain_of_War.png" />
  </query-continue>
  <query>
    <pages>
      <page ns="6" title="File:Bazaar Dragon Eggs.png" missing="" />
      <page ns="6" title="File:Bazaar items.png" missing="" />
      <page ns="6" title="File:Building Breeding Pit.png" missing="" />
      <page ns="6" title="File:Building Cave of Crystals.png" missing="" />
      <page ns="6" title="File:Building Crystal Tower.png" missing="" />
      <page ns="6" title="File:Building Crystalline Catapult.png" missing="" />
      <page pageid="39" ns="6" title="File:BarraDeMenú Botón Héroes.png" />
      <page pageid="44" ns="6" title="File:Barra de Mana.png" />
      <page pageid="76" ns="6" title="File:Barra de menu magia.PNG" />
      <page pageid="243" ns="6" title="File:Barra exp Eroe.png" />
    </pages>
  </query>
</api>