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>
    <allfileusages afcontinue="Jy01.png|27" />
  </query-continue>
  <query>
    <allfileusages>
      <f ns="6" title="File:Bth ozone adjoint.jpeg" />
      <f ns="6" title="File:Bth ozone adjoint.jpeg" />
      <f ns="6" title="File:Curiesmall.PNG" />
      <f ns="6" title="File:DSC02787 1.jpg" />
      <f ns="6" title="File:Enso impacts.png" />
      <f ns="6" title="File:Feng et al 2023 ship COVID.jpeg" />
      <f ns="6" title="File:Feng et al 2023 ship COVID.jpeg" />
      <f ns="6" title="File:Feng et al 2023 ship COVID.jpeg" />
      <f ns="6" title="File:Group202207.jpg" />
      <f ns="6" title="File:Group outing 202108.jpg" />
    </allfileusages>
  </query>
</api>