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 arcontinue="Búnquers" />
  </query-continue>
  <query>
    <allredirects>
      <r ns="0" title="Balma de la Regullosa" />
      <r ns="0" title="Baluard de Sant Andreu (S. XVI)" />
      <r ns="0" title="Baluard de Sant Jaume (s. XVI)" />
      <r ns="0" title="Baluard de Sant Joan (s.XVI)" />
      <r ns="0" title="Baluard de Sant Jordi (s.XVI)" />
      <r ns="0" title="Barri dels pescadors" />
      <r ns="0" title="Barri hel·lenístic (s. III aC)" />
      <r ns="0" title="Base militar Aèria del Pení" />
      <r ns="0" title="Biblioteca Jaume Vicens Vives" />
      <r ns="0" title="Bomba del setge (s.XVII)" />
    </allredirects>
  </query>
</api>