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>
    <allfileusages gafcontinue="Bayernallee42a.jpg|6368" />
  </query-continue>
  <query>
    <pages>
      <page pageid="213" ns="0" title="Bacchus" />
      <page pageid="1027" ns="0" title="Wankdorf-Stadion" />
      <page pageid="3585" ns="0" title="Bahnhof Berlin Zoologischer Garten" />
      <page pageid="4864" ns="0" title="Überfall auf das Bankhaus Neelmeyer" />
      <page pageid="5234" ns="0" title="Koenigsallee 46, 14193 Berlin" />
      <page pageid="5235" ns="14" title="Kategorie:Drehort &quot;Ron und Tanja&quot;" />
      <page pageid="5240" ns="0" title="Eylauer Straße 7, 10965 Berlin" />
      <page pageid="5243" ns="0" title="Tiergartenquelle" />
      <page pageid="6367" ns="0" title="Bayernallee 42a, 14052 Berlin" />
    </pages>
  </query>
</api>