You are looking at the HTML representation of the DBG 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 DBG format, set format=dbg.
See the complete documentation, or API help for more information. 
array (
  'query' => 
  array (
    'namespaces' => 
    array (
      -2 => 
      array (
        'id' => -2,
        'case' => 'first-letter',
        '*' => 'Media',
        'canonical' => 'Media',
      ),
      -1 => 
      array (
        'id' => -1,
        'case' => 'first-letter',
        '*' => 'Toiminnot',
        'canonical' => 'Special',
      ),
      0 => 
      array (
        'id' => 0,
        'case' => 'first-letter',
        '*' => '',
        'content' => '',
      ),
      1 => 
      array (
        'id' => 1,
        'case' => 'first-letter',
        '*' => 'Keskustelu',
        'subpages' => '',
        'canonical' => 'Talk',
      ),
      2 => 
      array (
        'id' => 2,
        'case' => 'first-letter',
        '*' => 'Käyttäjä',
        'subpages' => '',
        'canonical' => 'User',
      ),
      3 => 
      array (
        'id' => 3,
        'case' => 'first-letter',
        '*' => 'Keskustelu käyttäjästä',
        'subpages' => '',
        'canonical' => 'User talk',
      ),
      4 => 
      array (
        'id' => 4,
        'case' => 'first-letter',
        '*' => 'Finnish Wiki',
        'canonical' => 'Project',
      ),
      5 => 
      array (
        'id' => 5,
        'case' => 'first-letter',
        '*' => 'Keskustelu Finnish Wikistä',
        'subpages' => '',
        'canonical' => 'Project talk',
      ),
      6 => 
      array (
        'id' => 6,
        'case' => 'first-letter',
        '*' => 'Tiedosto',
        'canonical' => 'File',
      ),
      7 => 
      array (
        'id' => 7,
        'case' => 'first-letter',
        '*' => 'Keskustelu tiedostosta',
        'subpages' => '',
        'canonical' => 'File talk',
      ),
      8 => 
      array (
        'id' => 8,
        'case' => 'first-letter',
        '*' => 'Järjestelmäviesti',
        'subpages' => '',
        'canonical' => 'MediaWiki',
      ),
      9 => 
      array (
        'id' => 9,
        'case' => 'first-letter',
        '*' => 'Keskustelu järjestelmäviestistä',
        'subpages' => '',
        'canonical' => 'MediaWiki talk',
      ),
      10 => 
      array (
        'id' => 10,
        'case' => 'first-letter',
        '*' => 'Malline',
        'canonical' => 'Template',
      ),
      11 => 
      array (
        'id' => 11,
        'case' => 'first-letter',
        '*' => 'Keskustelu mallineesta',
        'subpages' => '',
        'canonical' => 'Template talk',
      ),
      12 => 
      array (
        'id' => 12,
        'case' => 'first-letter',
        '*' => 'Ohje',
        'canonical' => 'Help',
      ),
      13 => 
      array (
        'id' => 13,
        'case' => 'first-letter',
        '*' => 'Keskustelu ohjeesta',
        'subpages' => '',
        'canonical' => 'Help talk',
      ),
      14 => 
      array (
        'id' => 14,
        'case' => 'first-letter',
        '*' => 'Luokka',
        'canonical' => 'Category',
      ),
      15 => 
      array (
        'id' => 15,
        'case' => 'first-letter',
        '*' => 'Keskustelu luokasta',
        'subpages' => '',
        'canonical' => 'Category talk',
      ),
    ),
  ),
)