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="Languages|50" />
  </query-continue>
  <query>
    <pages>
      <page pageid="20" ns="0" title="Drawing:File" />
      <page pageid="50" ns="10" title="Template:Extension" />
      <page pageid="232" ns="0" title="DB:Global Manufacturers" />
      <page pageid="237" ns="0" title="DB:Global Equipment" />
      <page pageid="240" ns="0" title="DB:Global Signal Types" />
      <page pageid="255" ns="0" title="DB:Global Connectors" />
      <page pageid="256" ns="0" title="DB:Global Cable Types" />
      <page pageid="257" ns="0" title="DB:Global Color Codes" />
      <page pageid="281" ns="0" title="DB:Project Systems" />
      <page pageid="286" ns="0" title="DB:Project Cable" />
    </pages>
  </query>
</api>