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="BTS|2645" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1" ns="0" title="Pagina principale" />
      <page pageid="65" ns="0" title="BTS Treekun" />
      <page pageid="66" ns="0" title="BTS Basilisco" />
      <page pageid="67" ns="0" title="BTS Chrysos" />
      <page pageid="68" ns="0" title="BTS Cavaliere gigante" />
      <page pageid="74" ns="0" title="Glossario" />
      <page pageid="123" ns="0" title="TS del Laboratorio" />
      <page pageid="741" ns="0" title="RTS" />
      <page pageid="1331" ns="0" title="Materiali" />
      <page pageid="2161" ns="10" title="Template:Pagina principale/Body" />
    </pages>
  </query>
</api>