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>
    <interwikimap>
      <iw prefix="ar" local="" language="العربية" url="http://ar.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="bg" local="" language="български" url="http://bg.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="cs" local="" language="česky" url="http://cs.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="da" local="" language="dansk" url="http://da.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="de" local="" language="Deutsch" url="http://de.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="el" local="" language="Ελληνικά" url="http://el.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="es" local="" language="español" url="http://es.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="fi" local="" language="suomi" url="http://fi.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="fr" local="" language="français" url="http://fr.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="hewikisource" local="" url="http://he.wikisource.org/wiki/$1" wikiid="" api="" />
      <iw prefix="hr" local="" language="hrvatski" url="http://hr.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="hu" local="" language="magyar" url="http://hu.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="mediazilla" local="" url="https://bugzilla.wikimedia.org/$1" wikiid="" api="" />
      <iw prefix="nl" local="" language="Nederlands" url="http://nl.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="no" local="" language="‪norsk (bokmål)‬" url="http://no.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="pl" local="" language="polski" url="http://pl.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="pt" local="" language="português" url="http://pt.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="ro" local="" language="română" url="http://ro.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="ru" local="" language="русский" url="http://ru.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="sk" local="" language="slovenčina" url="http://sk.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="sv" local="" language="svenska" url="http://sv.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="tr" local="" language="Türkçe" url="http://tr.playmillion.com/wiki/$1" wikiid="" api="" />
      <iw prefix="wikibooks" local="" url="http://en.wikibooks.org/wiki/$1" wikiid="" api="" />
      <iw prefix="wikinews" local="" url="http://en.wikinews.org/wiki/$1" wikiid="" api="" />
      <iw prefix="wikipedia" local="" url="http://en.wikipedia.org/wiki/$1" wikiid="" api="" />
      <iw prefix="wikiquote" local="" url="http://en.wikiquote.org/wiki/$1" wikiid="" api="" />
      <iw prefix="wikisource" local="" url="http://wikisource.org/wiki/$1" wikiid="" api="" />
      <iw prefix="wikispecies" local="" url="http://species.wikimedia.org/wiki/$1" wikiid="" api="" />
      <iw prefix="wikiversity" local="" url="http://en.wikiversity.org/wiki/$1" wikiid="" api="" />
      <iw prefix="wikt" local="" url="http://en.wiktionary.org/wiki/$1" wikiid="" api="" />
      <iw prefix="wiktionary" local="" url="http://en.wiktionary.org/wiki/$1" wikiid="" api="" />
    </interwikimap>
  </query>
</api>