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="Main_Page" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="24" ns="0" title="DiHabs" />
      <p pageid="28" ns="0" title="DiLES" />
      <p pageid="46" ns="0" title="Fieldbus traffic simulation logs" />
      <p pageid="8" ns="0" title="GPS tracks" />
      <p pageid="33" ns="0" title="GPX data" />
      <p pageid="10" ns="0" title="Geographical distribution of nodes" />
      <p pageid="51" ns="0" title="Intrusion Detection in Fieldbuses" />
      <p pageid="85" ns="0" title="IoT Device ID" />
      <p pageid="44" ns="0" title="Jg460" />
      <p pageid="35" ns="0" title="KNX contactless" />
    </allpages>
  </query>
</api>