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="Building_CEGUI_for_Ogre_/_OgreRenderer" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="1949" ns="0" title="BuildStatus" />
      <p pageid="1781" ns="0" title="Build Configuration For Irrlicht" />
      <p pageid="1866" ns="0" title="Build PyCEGUI from source for Linux" />
      <p pageid="1868" ns="0" title="Build PyCEGUI from source for Windows" />
      <p pageid="1729" ns="0" title="Build configuration for Irrlicht" />
      <p pageid="1779" ns="0" title="Build from Source for Win32" />
      <p pageid="1508" ns="0" title="Build from source for Linux" />
      <p pageid="1520" ns="0" title="Build from source for OSX" />
      <p pageid="1487" ns="0" title="Build from source for Win32" />
      <p pageid="1939" ns="0" title="Building CEED for Windows" />
    </allpages>
  </query>
</api>