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>
    <alltransclusions gatcontinue="DesignDocument|175" />
  </query-continue>
  <query>
    <pages>
      <page pageid="95" ns="0" title="Libpg : A parametrics/constraint library" />
      <page pageid="100" ns="0" title="Revolve" />
      <page pageid="105" ns="0" title="Metropolis Light Transport" />
      <page pageid="107" ns="0" title="OpenGL GUI Framework" />
      <page pageid="167" ns="0" title="Geometry Service" />
      <page pageid="168" ns="0" title="GS Developers Guidelines" />
      <page pageid="169" ns="0" title="GS Requirements Standard" />
      <page pageid="170" ns="0" title="GS Actors Standard" />
      <page pageid="171" ns="0" title="GS Use-Cases Standard" />
      <page pageid="172" ns="0" title="GS Packages Standard" />
    </pages>
  </query>
</api>