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 (
  'warnings' => 
  array (
    'dbgfm' => 
    array (
      '*' => 'format=dbgfm has been deprecated. Please use format=jsonfm instead.',
    ),
  ),
  'query' => 
  array (
    'namespaces' => 
    array (
      -2 => 
      array (
        'id' => -2,
        'case' => 'first-letter',
        '*' => 'Media',
        'canonical' => 'Media',
      ),
      -1 => 
      array (
        'id' => -1,
        'case' => 'first-letter',
        '*' => 'Special',
        'canonical' => 'Special',
      ),
      0 => 
      array (
        'id' => 0,
        'case' => 'first-letter',
        '*' => '',
        'content' => '',
      ),
      1 => 
      array (
        'id' => 1,
        'case' => 'first-letter',
        '*' => 'Talk',
        'subpages' => '',
        'canonical' => 'Talk',
      ),
      2 => 
      array (
        'id' => 2,
        'case' => 'first-letter',
        '*' => 'User',
        'subpages' => '',
        'canonical' => 'User',
      ),
      3 => 
      array (
        'id' => 3,
        'case' => 'first-letter',
        '*' => 'User talk',
        'subpages' => '',
        'canonical' => 'User talk',
      ),
      4 => 
      array (
        'id' => 4,
        'case' => 'first-letter',
        '*' => 'CCRMA Wiki',
        'subpages' => '',
        'canonical' => 'Project',
      ),
      5 => 
      array (
        'id' => 5,
        'case' => 'first-letter',
        '*' => 'CCRMA Wiki talk',
        'subpages' => '',
        'canonical' => 'Project talk',
      ),
      6 => 
      array (
        'id' => 6,
        'case' => 'first-letter',
        '*' => 'File',
        'canonical' => 'File',
      ),
      7 => 
      array (
        'id' => 7,
        'case' => 'first-letter',
        '*' => 'File talk',
        'subpages' => '',
        'canonical' => 'File talk',
      ),
      8 => 
      array (
        'id' => 8,
        'case' => 'first-letter',
        '*' => 'MediaWiki',
        'subpages' => '',
        'canonical' => 'MediaWiki',
      ),
      9 => 
      array (
        'id' => 9,
        'case' => 'first-letter',
        '*' => 'MediaWiki talk',
        'subpages' => '',
        'canonical' => 'MediaWiki talk',
      ),
      10 => 
      array (
        'id' => 10,
        'case' => 'first-letter',
        '*' => 'Template',
        'canonical' => 'Template',
      ),
      11 => 
      array (
        'id' => 11,
        'case' => 'first-letter',
        '*' => 'Template talk',
        'subpages' => '',
        'canonical' => 'Template talk',
      ),
      12 => 
      array (
        'id' => 12,
        'case' => 'first-letter',
        '*' => 'Help',
        'subpages' => '',
        'canonical' => 'Help',
      ),
      13 => 
      array (
        'id' => 13,
        'case' => 'first-letter',
        '*' => 'Help talk',
        'subpages' => '',
        'canonical' => 'Help talk',
      ),
      14 => 
      array (
        'id' => 14,
        'case' => 'first-letter',
        '*' => 'Category',
        'canonical' => 'Category',
      ),
      15 => 
      array (
        'id' => 15,
        'case' => 'first-letter',
        '*' => 'Category talk',
        'subpages' => '',
        'canonical' => 'Category talk',
      ),
    ),
  ),
)