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>
    <allredirects garcontinue="IBHLink_S7++:Uhrzeitsynchronisation" />
  </query-continue>
  <query>
    <pages>
      <page pageid="390" ns="0" title="IBHLink:Historie" />
      <page pageid="380" ns="0" title="IBHLink S5++:LOGO! mit IBHLink S5++" />
      <page pageid="637" ns="0" title="IBHLink S5++:SIMATIC® S5 GraphPic®" />
      <page pageid="776" ns="0" title="IBHLink S5++:SIMATIC® S5 TIA Portal V11 WinCC flexible" />
      <page pageid="428" ns="0" title="IBHLink S7++:Inbetriebnahme IBHLink S7++" />
      <page pageid="379" ns="0" title="IBHLink S7++:LOGO! mit IBHLink S7++" />
      <page pageid="121" ns="0" title="IBHLink S7++:Parametrierung von Feldgeräten" />
      <page pageid="417" ns="0" title="IBHLink S7++:S7-1200 IBHLink S7++ S7-Verbindung" />
      <page pageid="392" ns="0" title="IBHLink S7++:S7-200 WinCC flexible" />
      <page pageid="597" ns="0" title="IBHLink S7++:S7-300/400 GraphPic®" />
    </pages>
  </query>
</api>