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="Czasomierz_lekcyjny" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1672" ns="0" title="Bloki kolorów" />
      <page pageid="1563" ns="0" title="Bloki kontrolne" />
      <page pageid="1666" ns="0" title="Bloki listowe" />
      <page pageid="1572" ns="0" title="Bloki logiczne" />
      <page pageid="1626" ns="0" title="Bloki matematyczne" />
      <page pageid="1684" ns="0" title="Bloki procedur" />
      <page pageid="1645" ns="0" title="Bloki tekstowe" />
      <page pageid="1673" ns="0" title="Bloki zmiennych" />
      <page pageid="606" ns="0" title="Bouncing Ball" />
      <page pageid="19" ns="0" title="Cykl życia motyla" />
    </pages>
  </query>
</api>