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="Edycja_lokalizacji|5" />
  </query-continue>
  <query>
    <pages>
      <page pageid="4" ns="0" title="IMO User" />
      <page pageid="5" ns="0" title="IMO Admin" />
      <page pageid="56" ns="0" title="Dodawanie agenta" />
      <page pageid="73" ns="0" title="IMO - Instrukcja dla użytkownika" />
      <page pageid="74" ns="0" title="IMO - Instrukcja dla administratora" />
    </pages>
  </query>
</api>