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 gafcontinue="Case_1.jpg" />
  </query-continue>
  <query>
    <pages>
      <page pageid="985" ns="6" title="File:Bios emmc.png" />
      <page pageid="945" ns="6" title="File:Bios enter shell.png" />
      <page pageid="948" ns="6" title="File:Bios main interface.png" />
      <page pageid="942" ns="6" title="File:Bios update in win10 1.PNG" />
      <page pageid="947" ns="6" title="File:Bios update in win10 2.PNG" />
      <page pageid="949" ns="6" title="File:Bios update interface.png" />
      <page pageid="546" ns="6" title="File:Boardnacar.png" />
      <page pageid="106" ns="6" title="File:Boot sdcard 1.jpg" />
      <page pageid="755" ns="6" title="File:Build-selected.png" />
      <page pageid="1096" ns="6" title="File:Can test.zip" />
    </pages>
  </query>
</api>