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="BMT_10_2015/Seite_1" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="11897" ns="0" title="BDs zum Thema &quot;Mit Französisch um die Welt" />
      <p pageid="3942" ns="0" title="BMT10 2007" />
      <p pageid="3941" ns="0" title="BMT10 2008" />
      <p pageid="3940" ns="0" title="BMT8 2008" />
      <p pageid="13192" ns="0" title="BMT 10 2014" />
      <p pageid="13193" ns="0" title="BMT 10 2014/Seite 1" />
      <p pageid="13194" ns="0" title="BMT 10 2014/Seite 2" />
      <p pageid="13195" ns="0" title="BMT 10 2014/Seite 3" />
      <p pageid="13196" ns="0" title="BMT 10 2014/Seite 4" />
      <p pageid="13171" ns="0" title="BMT 10 2015" />
    </allpages>
  </query>
</api>