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>
    <allpages>
      <p pageid="153" ns="0" title="Boulder" />
      <p pageid="127" ns="0" title="Butterfly knife" />
      <p pageid="27" ns="0" title="Cтаты" />
      <p pageid="33" ns="0" title="Eviscerator knife" />
      <p pageid="93" ns="0" title="Gefängnis" />
      <p pageid="113" ns="0" title="HistoryMan" />
      <p pageid="128" ns="0" title="Jackal knife" />
      <p pageid="140" ns="0" title="Laser Rifle XJ45" />
      <p pageid="137" ns="0" title="Laser pistol XJ25" />
      <p pageid="155" ns="0" title="Life crystal" />
    </allpages>
  </query>
  <query-continue>
    <allpages apcontinue="Main_Page" />
  </query-continue>
</api>