You are looking at the HTML representation of the TXT 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 TXT format, set format=txt.
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
                            [*] => 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
                            [*] => Counting Opinions
                            [subpages] => 
                            [canonical] => Project
                        )

                    [5] => Array
                        (
                            [id] => 5
                            [case] => first-letter
                            [*] => Counting Opinions 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
                        )

                    [100] => Array
                        (
                            [id] => 100
                            [case] => first-letter
                            [*] => LibSat
                            [subpages] => 
                            [canonical] => LibSat
                            [content] => 
                        )

                    [101] => Array
                        (
                            [id] => 101
                            [case] => first-letter
                            [*] => LibSat talk
                            [canonical] => LibSat talk
                        )

                    [102] => Array
                        (
                            [id] => 102
                            [case] => first-letter
                            [*] => LibPAS
                            [subpages] => 
                            [canonical] => LibPAS
                            [content] => 
                        )

                    [103] => Array
                        (
                            [id] => 103
                            [case] => first-letter
                            [*] => LibPAS talk
                            [canonical] => LibPAS talk
                        )

                    [104] => Array
                        (
                            [id] => 104
                            [case] => first-letter
                            [*] => InformsUs
                            [subpages] => 
                            [canonical] => InformsUs
                            [content] => 
                        )

                    [105] => Array
                        (
                            [id] => 105
                            [case] => first-letter
                            [*] => InformsUs talk
                            [canonical] => InformsUs talk
                        )

                    [106] => Array
                        (
                            [id] => 106
                            [case] => first-letter
                            [*] => News
                            [subpages] => 
                            [canonical] => News
                            [content] => 
                        )

                    [107] => Array
                        (
                            [id] => 107
                            [case] => first-letter
                            [*] => News talk
                            [canonical] => News talk
                        )

                    [108] => Array
                        (
                            [id] => 108
                            [case] => first-letter
                            [*] => Staff
                            [subpages] => 
                            [canonical] => Staff
                            [content] => 
                        )

                    [109] => Array
                        (
                            [id] => 109
                            [case] => first-letter
                            [*] => Staff talk
                            [canonical] => Staff talk
                        )

                    [110] => Array
                        (
                            [id] => 110
                            [case] => first-letter
                            [*] => Services
                            [subpages] => 
                            [canonical] => Services
                            [content] => 
                        )

                    [111] => Array
                        (
                            [id] => 111
                            [case] => first-letter
                            [*] => Services talk
                            [canonical] => Services talk
                        )

                    [112] => Array
                        (
                            [id] => 112
                            [case] => first-letter
                            [*] => Studies
                            [subpages] => 
                            [canonical] => Studies
                            [content] => 
                        )

                    [113] => Array
                        (
                            [id] => 113
                            [case] => first-letter
                            [*] => Studies talk
                            [canonical] => Studies talk
                        )

                    [114] => Array
                        (
                            [id] => 114
                            [case] => first-letter
                            [*] => Support
                            [subpages] => 
                            [canonical] => Support
                            [content] => 
                        )

                    [115] => Array
                        (
                            [id] => 115
                            [case] => first-letter
                            [*] => Support talk
                            [canonical] => Support talk
                        )

                    [116] => Array
                        (
                            [id] => 116
                            [case] => first-letter
                            [*] => Minutes
                            [subpages] => 
                            [canonical] => Minutes
                        )

                    [117] => Array
                        (
                            [id] => 117
                            [case] => first-letter
                            [*] => Minutes talk
                            [canonical] => Minutes talk
                        )

                    [118] => Array
                        (
                            [id] => 118
                            [case] => first-letter
                            [*] => CSS
                            [subpages] => 
                            [canonical] => CSS
                            [content] => 
                        )

                    [119] => Array
                        (
                            [id] => 119
                            [case] => first-letter
                            [*] => CSS talk
                            [canonical] => CSS talk
                        )

                    [200] => Array
                        (
                            [id] => 200
                            [case] => first-letter
                            [*] => IPEDS
                            [subpages] => 
                            [canonical] => IPEDS
                            [content] => 
                        )

                    [201] => Array
                        (
                            [id] => 201
                            [case] => first-letter
                            [*] => IPEDS talk
                            [canonical] => IPEDS talk
                        )

                    [274] => Array
                        (
                            [id] => 274
                            [case] => first-letter
                            [*] => Widget
                            [subpages] => 
                            [canonical] => Widget
                            [content] => 
                        )

                    [275] => Array
                        (
                            [id] => 275
                            [case] => first-letter
                            [*] => Widget talk
                            [subpages] => 
                            [canonical] => Widget talk
                        )

                    [302] => Array
                        (
                            [id] => 302
                            [case] => first-letter
                            [*] => Property
                            [canonical] => Property
                        )

                    [303] => Array
                        (
                            [id] => 303
                            [case] => first-letter
                            [*] => Property talk
                            [subpages] => 
                            [canonical] => Property talk
                        )

                    [306] => Array
                        (
                            [id] => 306
                            [case] => first-letter
                            [*] => Form
                            [canonical] => Form
                        )

                    [307] => Array
                        (
                            [id] => 307
                            [case] => first-letter
                            [*] => Form talk
                            [subpages] => 
                            [canonical] => Form talk
                        )

                    [308] => Array
                        (
                            [id] => 308
                            [case] => first-letter
                            [*] => Concept
                            [canonical] => Concept
                        )

                    [309] => Array
                        (
                            [id] => 309
                            [case] => first-letter
                            [*] => Concept talk
                            [canonical] => Concept talk
                        )

                )

        )

)