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>
    <pages>
      <page pageid="130" ns="0" title="Portada" contentmodel="wikitext" pagelanguage="eu" touched="2024-05-10T09:34:21Z" lastrevid="7288" counter="418430" length="1239" />
      <page pageid="1433" ns="0" title="Tratado de Paz" contentmodel="wikitext" pagelanguage="eu" touched="2015-01-28T14:47:15Z" lastrevid="7031" counter="8636" length="1012" />
      <page pageid="1436" ns="0" title="Bilbao y la música" contentmodel="wikitext" pagelanguage="eu" touched="2015-02-04T10:03:53Z" lastrevid="7021" counter="17323" length="1012" />
      <page pageid="1567" ns="0" title="San Sebastián y Gipuzkoa en el siglo XIX" contentmodel="wikitext" pagelanguage="eu" touched="2015-02-04T10:01:37Z" lastrevid="7064" counter="4265" length="1024" />
      <page pageid="1830" ns="0" title="Familia Vildosola" contentmodel="wikitext" pagelanguage="eu" touched="2015-02-04T10:00:07Z" lastrevid="7193" counter="6724" length="1036" />
      <page pageid="3241" ns="0" title="Real Sociedad Bascongada de Amigos del País" contentmodel="wikitext" pagelanguage="eu" touched="2015-01-28T15:39:56Z" lastrevid="7035" counter="13140" length="1020" />
      <page pageid="3347" ns="0" title="La fábrica de vidrio de Lamiaco" contentmodel="wikitext" pagelanguage="eu" touched="2015-02-02T09:44:46Z" lastrevid="7043" counter="2302" length="1012" new="" />
    </pages>
  </query>
</api>