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="Profil_użytkownika" />
  </query-continue>
  <query>
    <pages>
      <page ns="0" title="Panel redaktora-koordynatora" missing="" />
      <page pageid="1351" ns="0" title="Biuletyn" />
      <page pageid="52" ns="0" title="Blog biuletynu" />
      <page pageid="1337" ns="0" title="Dodawanie słów kluczowych" />
      <page pageid="9" ns="0" title="Edukacja i praca" />
      <page pageid="16" ns="0" title="Logowanie" />
      <page pageid="20" ns="0" title="Newsletter" />
      <page pageid="29" ns="0" title="Panel administratora" />
      <page pageid="7" ns="0" title="Panel użytkownika portalu" />
      <page pageid="3" ns="0" title="Portal &quot;Biuletyn Polonistyczny&quot; – założenia, cele i priorytety projektu" />
    </pages>
  </query>
</api>