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>
    <allpages apcontinue="Energie" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="178" ns="0" title="Bahnknoten München" />
      <p pageid="1629" ns="0" title="Bibliothek 21" />
      <p pageid="1630" ns="0" title="Bibliothek 21/Austattung Innen" />
      <p pageid="1631" ns="0" title="Bibliothek 21/Technik Innen" />
      <p pageid="388" ns="0" title="Deutsche Bahn" />
      <p pageid="1810" ns="0" title="Deutsche Bahn/Fremdsteuerung" />
      <p pageid="1813" ns="0" title="Deutsche Bahn/Netzwerk" />
      <p pageid="399" ns="0" title="Deutsche Bahn/Strategie" />
      <p pageid="1750" ns="0" title="Deutsche Bahn/Wissenschaft" />
      <p pageid="1771" ns="0" title="Empfohlene Dokumentationen" />
    </allpages>
  </query>
</api>