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>
    <alllinks galcontinue="Buildout|306" />
  </query-continue>
  <query>
    <pages>
      <page pageid="56" ns="0" title="Equips" />
      <page pageid="312" ns="0" title="Entorns de desenvolupament" />
      <page pageid="442" ns="0" title="Administració de Bases de Dades" />
      <page pageid="450" ns="0" title="Administració de Sistemes Operatius" />
      <page pageid="457" ns="0" title="GNU/Linux" />
      <page pageid="469" ns="0" title="Bash script" />
      <page pageid="487" ns="0" title="Programació web entorn servidor" />
      <page pageid="493" ns="0" title="PHP sessions" />
    </pages>
  </query>
</api>