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="Citrix®_x86_64-Client_Version_13.10_auf_Ubuntu_Linux_18.04_installieren_(4.15.0-36-generic)" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="252" ns="0" title="BananaPro" />
      <p pageid="253" ns="0" title="BananaPro (Armbian ab 1/2018)" />
      <p pageid="139" ns="0" title="BananaPro (Bananian bis 1/2018)" />
      <p pageid="345" ns="0" title="Bluetooth-Maus mit iPad Pro (11 Zoll MU102FD / iPad OS 13.3.1) verbinden" />
      <p pageid="291" ns="0" title="C64" />
      <p pageid="73" ns="0" title="Citrix® Receiver for Windows 3.0 (x86) auf Microsoft Windows 7 Professional SP1 installieren (Version 6.1.7601)" />
      <p pageid="74" ns="0" title="Citrix® Receiver x86-Client Version 11 auf Microsoft Windows 7 Professional SP1 installieren (Version 6.1.7601)" />
      <p pageid="372" ns="0" title="Citrix® WorkSpace App 1808 auf Ubuntu Linux Ubuntu 20.04.1 LTS installieren (5.4.0-53-generic)" />
      <p pageid="12" ns="0" title="Citrix® x86-Client Version 11 auf Ubuntu Linux 10.2 installieren (2.6.31-15-generic-pae)" />
      <p pageid="249" ns="0" title="Citrix® x86-Client Version 13 auf Ubuntu Linux 16.04 installieren (4.4.0-89-generic)" />
    </allpages>
  </query>
</api>