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="Bugatti_Type_102" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="1771" ns="0" title="BC 049 (4963)" />
      <p pageid="6600" ns="0" title="Bugantics" />
      <p pageid="5768" ns="0" title="Bugatti - From Milan to Molsheim" />
      <p pageid="6357" ns="0" title="Bugatti 1939" />
      <p pageid="2018" ns="0" title="Bugatti Airplane" />
      <p pageid="1892" ns="0" title="Bugatti Autorail" />
      <p pageid="5760" ns="0" title="Bugatti EB110 scale models" />
      <p pageid="5747" ns="0" title="Bugatti EB112 scale models" />
      <p pageid="3914" ns="0" title="Bugatti Liberation Front" />
      <p pageid="1421" ns="0" title="Bugatti Type 101" />
    </allpages>
  </query>
</api>