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="Bg|1451" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1216" ns="0" title="Vilém Flusser" />
      <page pageid="5774" ns="0" title="El Lissitzky" />
      <page pageid="11452" ns="0" title="John Amos Comenius" />
      <page pageid="12588" ns="0" title="Fernand Léger" />
      <page pageid="13765" ns="0" title="Pablo Picasso" />
      <page pageid="20801" ns="0" title="Hannah Höch" />
      <page pageid="21922" ns="0" title="Raoul Hausmann" />
      <page pageid="22005" ns="0" title="Georges Braque" />
      <page pageid="22009" ns="0" title="Jacques Lipchitz" />
      <page pageid="25100" ns="0" title="Tacita Dean" />
    </pages>
  </query>
</api>