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="Club|972" />
  </query-continue>
  <query>
    <pages>
      <page pageid="951" ns="0" title="(Not Very) Current events" />
      <page pageid="990" ns="0" title="Making new pages" />
      <page pageid="2214" ns="0" title="Books" />
      <page pageid="2240" ns="0" title="Poetry:On a Certain Lady at Court" />
      <page pageid="2244" ns="0" title="Poetry:Ozymandius" />
      <page pageid="2247" ns="0" title="Poetry:I never look at you" />
      <page pageid="2255" ns="0" title="Linux/Networking Setup" />
      <page pageid="2257" ns="0" title="Linux/Kernel Configuration" />
      <page pageid="2271" ns="0" title="Maps" />
      <page pageid="2786" ns="0" title="Linux/X Configuration" />
    </pages>
  </query>
</api>