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="ISBoxerNews|664" />
  </query-continue>
  <query>
    <pages>
      <page pageid="630" ns="0" title="ISBoxer 42" />
      <page pageid="640" ns="0" title="Follow/Assist Mode" />
      <page pageid="642" ns="0" title="ISBoxer 42:Quick Setup Wizard" />
      <page pageid="647" ns="0" title="ISBoxer 42:Common modifications" />
      <page pageid="648" ns="0" title="ISBoxer 42:Configuration Style" />
      <page pageid="658" ns="0" title="ISBoxer 42:MMO - Standard Configuration" />
      <page pageid="665" ns="0" title="ISBoxer 42:Detailed Start Guide" />
    </pages>
  </query>
</api>