You are looking at the HTML representation of the DUMP 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 DUMP format, set format=dump.
See the complete documentation, or API help for more information.
array(2) {
  ["warnings"]=>
  array(1) {
    ["dumpfm"]=>
    array(1) {
      ["*"]=>
      string(68) "format=dumpfm has been deprecated. Please use format=jsonfm instead."
    }
  }
  ["query"]=>
  array(1) {
    ["namespaces"]=>
    array(28) {
      [-2]=>
      array(4) {
        ["id"]=>
        int(-2)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(5) "Media"
        ["canonical"]=>
        string(5) "Media"
      }
      [-1]=>
      array(5) {
        ["id"]=>
        int(-1)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(7) "Special"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(7) "Special"
      }
      [0]=>
      array(5) {
        ["id"]=>
        int(0)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(0) ""
        ["subpages"]=>
        string(0) ""
        ["content"]=>
        string(0) ""
      }
      [1]=>
      array(5) {
        ["id"]=>
        int(1)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(4) "Talk"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(4) "Talk"
      }
      [2]=>
      array(5) {
        ["id"]=>
        int(2)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(4) "User"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(4) "User"
      }
      [3]=>
      array(5) {
        ["id"]=>
        int(3)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(9) "User talk"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(9) "User talk"
      }
      [4]=>
      array(5) {
        ["id"]=>
        int(4)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(17) "Citizendium Pilot"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(7) "Project"
      }
      [5]=>
      array(5) {
        ["id"]=>
        int(5)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(22) "Citizendium Pilot Talk"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(12) "Project talk"
      }
      [6]=>
      array(4) {
        ["id"]=>
        int(6)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(4) "File"
        ["canonical"]=>
        string(4) "File"
      }
      [7]=>
      array(5) {
        ["id"]=>
        int(7)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(9) "File talk"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(9) "File talk"
      }
      [8]=>
      array(5) {
        ["id"]=>
        int(8)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(9) "MediaWiki"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(9) "MediaWiki"
      }
      [9]=>
      array(5) {
        ["id"]=>
        int(9)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(14) "MediaWiki talk"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(14) "MediaWiki talk"
      }
      [10]=>
      array(5) {
        ["id"]=>
        int(10)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(8) "Template"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(8) "Template"
      }
      [11]=>
      array(5) {
        ["id"]=>
        int(11)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(13) "Template talk"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(13) "Template talk"
      }
      [12]=>
      array(5) {
        ["id"]=>
        int(12)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(4) "Help"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(4) "Help"
      }
      [13]=>
      array(5) {
        ["id"]=>
        int(13)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(9) "Help talk"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(9) "Help talk"
      }
      [14]=>
      array(4) {
        ["id"]=>
        int(14)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(8) "Category"
        ["canonical"]=>
        string(8) "Category"
      }
      [15]=>
      array(5) {
        ["id"]=>
        int(15)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(13) "Category talk"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(13) "Category talk"
      }
      [100]=>
      array(5) {
        ["id"]=>
        int(100)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(2) "CZ"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(2) "CZ"
      }
      [101]=>
      array(5) {
        ["id"]=>
        int(101)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(7) "CZ Talk"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(7) "CZ Talk"
      }
      [102]=>
      array(5) {
        ["id"]=>
        int(102)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(2) "TI"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(2) "TI"
      }
      [103]=>
      array(5) {
        ["id"]=>
        int(103)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(7) "TI Talk"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(7) "TI Talk"
      }
      [104]=>
      array(5) {
        ["id"]=>
        int(104)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(3) "WYA"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(3) "WYA"
      }
      [105]=>
      array(5) {
        ["id"]=>
        int(105)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(8) "WYA Talk"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(8) "WYA Talk"
      }
      [106]=>
      array(4) {
        ["id"]=>
        int(106)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(5) "Forum"
        ["canonical"]=>
        string(5) "Forum"
      }
      [107]=>
      array(4) {
        ["id"]=>
        int(107)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(10) "Forum Talk"
        ["canonical"]=>
        string(10) "Forum Talk"
      }
      [274]=>
      array(4) {
        ["id"]=>
        int(274)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(6) "Widget"
        ["canonical"]=>
        string(6) "Widget"
      }
      [275]=>
      array(5) {
        ["id"]=>
        int(275)
        ["case"]=>
        string(12) "first-letter"
        ["*"]=>
        string(11) "Widget talk"
        ["subpages"]=>
        string(0) ""
        ["canonical"]=>
        string(11) "Widget talk"
      }
    }
  }
}