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="Draci_snem.jpg|441" />
  </query-continue>
  <query>
    <pages>
      <page pageid="57" ns="2" title="Uživatel:StriderCZ/Herní deník Might&amp;Magic II: The gates to Another Worlds" />
      <page pageid="438" ns="2" title="Uživatel:StriderCZ/Herní deník Might&amp;Magic I: The Secret of Inner Sanctum" />
      <page pageid="440" ns="3" title="Diskuse s uživatelem:Majk/1" />
      <page pageid="441" ns="2" title="Uživatel:Ali/Herní deník Mac verze Might&amp;Magic I" />
    </pages>
  </query>
</api>