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>
    <allredirects garcontinue="CAAD" />
  </query-continue>
  <query>
    <pages>
      <page pageid="2266" ns="0" title="BASIC" />
      <page pageid="3281" ns="0" title="Batería de iones de litio" />
      <page pageid="11934" ns="0" title="Bawareth Perfect MSX1" />
      <page pageid="6800" ns="0" title="Bits por segundo" />
      <page pageid="10092" ns="0" title="Boxeo" />
      <page pageid="6110" ns="0" title="Bull" />
      <page pageid="2081" ns="0" title="Bulletin Board System" />
      <page pageid="1695" ns="0" title="Bus ISA" />
      <page pageid="2155" ns="0" title="Byte" />
      <page pageid="2644" ns="0" title="C.ITOH ProWriter Junior" />
    </pages>
  </query>
</api>