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>
    <pages>
      <page pageid="208" ns="0" title="Zabbix - HP IPMI (ILO) Hardware Überwachung" />
      <page pageid="229" ns="0" title="Windows Key hinzufügen/ändern/entfernen" />
      <page pageid="233" ns="0" title="PowerShell Hyper-V" />
      <page pageid="242" ns="0" title="Bug: ESXi-Host empfängt keine:Cisco ACI ARP Response mit der Mellanox 10/40GB NIC" />
      <page pageid="244" ns="0" title="Beispiele: PowerShell Funtionen" />
      <page pageid="246" ns="0" title="PowerShell Passwort verschlüsseln" />
      <page pageid="321" ns="0" title="Receive Side Scaling (RSS-Settings)" />
      <page pageid="615" ns="0" title="InfluxDB: Downsampling" />
    </pages>
  </query>
</api>