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="504" ns="0" title="Back Pain: What Solutions Can Make You Feel Better?" />
      <p pageid="76" ns="0" title="Basic equipment" />
      <p pageid="253" ns="0" title="Benutzernamen registrieren" />
      <p pageid="452" ns="0" title="Blank Text Permanent" />
      <p pageid="406" ns="0" title="Bloodlord of Vaasgoth" />
      <p pageid="62" ns="0" title="Boost creature type" />
      <p pageid="48" ns="0" title="Bugs" />
      <p pageid="502" ns="0" title="By What Technique Spider Veins Can Be Removed?" />
      <p pageid="285" ns="0" title="COMMUNITY DLC Tutorial - Card Editing" />
      <p pageid="278" ns="0" title="COMMUNITY DLC Tutorial - Setup Tortoise SVN" />
    </allpages>
  </query>
  <query-continue>
    <allpages apcontinue="Can_Pedialyte_Offer_Effective_Results_To_Replenish_Electrolytes?" />
  </query-continue>
</api>