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>
    <allpages apcontinue="Lesson_0.5_-_quick_fix" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="5" ns="0" title="Bo3b&#039;s School for Shaderhackers" />
      <p pageid="79" ns="0" title="Canonical Stereo Code" />
      <p pageid="141" ns="0" title="DarkStarSword example fixes" />
      <p pageid="52" ns="0" title="Default DX9Settings.ini" />
      <p pageid="115" ns="0" title="Driver Profile Settings" />
      <p pageid="157" ns="0" title="Fixing bookmarks" />
      <p pageid="80" ns="0" title="Game Fixing Strategy" />
      <p pageid="63" ns="0" title="HelixMod Feature List" />
      <p pageid="51" ns="0" title="Hot tips" />
      <p pageid="10" ns="0" title="Lesson 0" />
    </allpages>
  </query>
</api>