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="Bug:_Vergrössern_eines_Datastores_nicht_möglich" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="416" ns="0" title="BCDEdit (Test-Mode)" />
      <p pageid="418" ns="0" title="BIOS/UEFI-Version" />
      <p pageid="173" ns="0" title="BITS-Transfer" />
      <p pageid="244" ns="0" title="Beispiele: PowerShell Funtionen" />
      <p pageid="243" ns="0" title="Beispiele: PowerShell Funtionen und Schleifen" />
      <p pageid="296" ns="0" title="Beschädigte/fehlende DLL-Dateien reparieren (SFC/DISM)" />
      <p pageid="316" ns="0" title="Blackout-Time (VM Live Migration)" />
      <p pageid="157" ns="0" title="Bluescreen" />
      <p pageid="242" ns="0" title="Bug: ESXi-Host empfängt keine:Cisco ACI ARP Response mit der Mellanox 10/40GB NIC" />
      <p pageid="240" ns="0" title="Bug: ESXi-Host empfängt keine Cisco ACI ARP Response mit der Mellanox 10/40GB NIC" />
    </allpages>
  </query>
</api>