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',
        '*' => 'Média',
        'canonical' => 'Media',
      ),
      -1 => 
      array (
        'id' => -1,
        'case' => 'first-letter',
        '*' => 'Speciální',
        'canonical' => 'Special',
      ),
      0 => 
      array (
        'id' => 0,
        'case' => 'first-letter',
        '*' => '',
        'content' => '',
      ),
      1 => 
      array (
        'id' => 1,
        'case' => 'first-letter',
        '*' => 'Diskuse',
        'subpages' => '',
        'canonical' => 'Talk',
      ),
      2 => 
      array (
        'id' => 2,
        'case' => 'first-letter',
        '*' => 'Uživatel',
        'subpages' => '',
        'canonical' => 'User',
      ),
      3 => 
      array (
        'id' => 3,
        'case' => 'first-letter',
        '*' => 'Diskuse s uživatelem',
        'subpages' => '',
        'canonical' => 'User talk',
      ),
      4 => 
      array (
        'id' => 4,
        'case' => 'first-letter',
        '*' => 'OldComp Wiki',
        'subpages' => '',
        'canonical' => 'Project',
      ),
      5 => 
      array (
        'id' => 5,
        'case' => 'first-letter',
        '*' => 'Diskuse k OldComp Wiki',
        'subpages' => '',
        'canonical' => 'Project talk',
      ),
      6 => 
      array (
        'id' => 6,
        'case' => 'first-letter',
        '*' => 'Soubor',
        'canonical' => 'File',
      ),
      7 => 
      array (
        'id' => 7,
        'case' => 'first-letter',
        '*' => 'Diskuse k souboru',
        'subpages' => '',
        'canonical' => 'File talk',
      ),
      8 => 
      array (
        'id' => 8,
        'case' => 'first-letter',
        '*' => 'MediaWiki',
        'subpages' => '',
        'canonical' => 'MediaWiki',
      ),
      9 => 
      array (
        'id' => 9,
        'case' => 'first-letter',
        '*' => 'Diskuse k MediaWiki',
        'subpages' => '',
        'canonical' => 'MediaWiki talk',
      ),
      10 => 
      array (
        'id' => 10,
        'case' => 'first-letter',
        '*' => 'Šablona',
        'canonical' => 'Template',
      ),
      11 => 
      array (
        'id' => 11,
        'case' => 'first-letter',
        '*' => 'Diskuse k šabloně',
        'subpages' => '',
        'canonical' => 'Template talk',
      ),
      12 => 
      array (
        'id' => 12,
        'case' => 'first-letter',
        '*' => 'Nápověda',
        'subpages' => '',
        'canonical' => 'Help',
      ),
      13 => 
      array (
        'id' => 13,
        'case' => 'first-letter',
        '*' => 'Diskuse k nápovědě',
        'subpages' => '',
        'canonical' => 'Help talk',
      ),
      14 => 
      array (
        'id' => 14,
        'case' => 'first-letter',
        '*' => 'Kategorie',
        'canonical' => 'Category',
      ),
      15 => 
      array (
        'id' => 15,
        'case' => 'first-letter',
        '*' => 'Diskuse ke kategorii',
        'subpages' => '',
        'canonical' => 'Category talk',
      ),
    ),
  ),
)