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>
    <pages>
      <page ns="0" title="Writing Android plugins" missing="" />
      <page pageid="11" ns="0" title="Code of Conduct" />
      <page pageid="6" ns="0" title="Deployment" />
      <page pageid="7" ns="0" title="Gideros plugins" />
      <page pageid="4" ns="0" title="Installing Gideros Studio" />
      <page pageid="10" ns="0" title="Menu shortcuts and accelerators" />
      <page pageid="2" ns="0" title="Release notes" />
      <page pageid="5" ns="0" title="Running Gideros Studio under Linux" />
      <page pageid="9" ns="0" title="Showing Status Bar" />
      <page pageid="3" ns="0" title="Ultimate Guide to Gideros Studio" />
    </pages>
  </query>
</api>