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="Compendio_dei_santi,_teologi,_mistici_e_profeti_oggi_dimenticati" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="157" ns="0" title="Ban number" />
      <p pageid="168" ns="0" title="Bicholim conflict" />
      <p pageid="131" ns="0" title="Book suggestions" />
      <p pageid="9" ns="0" title="Books" />
      <p pageid="152" ns="0" title="Carteggio con Simplicio" />
      <p pageid="153" ns="0" title="Cartridge tilting" />
      <p pageid="98" ns="0" title="Catalogue of favourite books" />
      <p pageid="171" ns="0" title="Censorship of The Amazing World of Gumball in Australia" />
      <p pageid="128" ns="0" title="Christoffel symbols" />
      <p pageid="129" ns="0" title="Cineforum di Breganze" />
    </allpages>
  </query>
</api>