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
                            [*] => 2628Climator
                            [subpages] => 
                            [canonical] => Project
                        )

                    [5] => Array
                        (
                            [id] => 5
                            [case] => first-letter
                            [*] => 2628Climator 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
                            [*] => project01
                            [canonical] => project01
                        )

                    [101] => Array
                        (
                            [id] => 101
                            [case] => first-letter
                            [*] => project01 talk
                            [canonical] => project01 talk
                        )

                    [102] => Array
                        (
                            [id] => 102
                            [case] => first-letter
                            [*] => project02
                            [canonical] => project02
                        )

                    [103] => Array
                        (
                            [id] => 103
                            [case] => first-letter
                            [*] => project02 talk
                            [canonical] => project02 talk
                        )

                    [104] => Array
                        (
                            [id] => 104
                            [case] => first-letter
                            [*] => project03
                            [canonical] => project03
                        )

                    [105] => Array
                        (
                            [id] => 105
                            [case] => first-letter
                            [*] => project03 talk
                            [canonical] => project03 talk
                        )

                    [106] => Array
                        (
                            [id] => 106
                            [case] => first-letter
                            [*] => project04
                            [canonical] => project04
                        )

                    [107] => Array
                        (
                            [id] => 107
                            [case] => first-letter
                            [*] => project04 talk
                            [canonical] => project04 talk
                        )

                    [108] => Array
                        (
                            [id] => 108
                            [case] => first-letter
                            [*] => project05
                            [canonical] => project05
                        )

                    [109] => Array
                        (
                            [id] => 109
                            [case] => first-letter
                            [*] => project05 talk
                            [canonical] => project05 talk
                        )

                    [110] => Array
                        (
                            [id] => 110
                            [case] => first-letter
                            [*] => project06
                            [canonical] => project06
                        )

                    [111] => Array
                        (
                            [id] => 111
                            [case] => first-letter
                            [*] => project06 talk
                            [canonical] => project06 talk
                        )

                    [112] => Array
                        (
                            [id] => 112
                            [case] => first-letter
                            [*] => project07
                            [canonical] => project07
                        )

                    [113] => Array
                        (
                            [id] => 113
                            [case] => first-letter
                            [*] => project07 talk
                            [canonical] => project07 talk
                        )

                    [114] => Array
                        (
                            [id] => 114
                            [case] => first-letter
                            [*] => project08
                            [canonical] => project08
                        )

                    [115] => Array
                        (
                            [id] => 115
                            [case] => first-letter
                            [*] => project08 talk
                            [canonical] => project08 talk
                        )

                    [200] => Array
                        (
                            [id] => 200
                            [case] => first-letter
                            [*] => UserWiki
                            [canonical] => UserWiki
                        )

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

                    [202] => Array
                        (
                            [id] => 202
                            [case] => first-letter
                            [*] => User profile
                            [canonical] => User profile
                        )

                    [203] => Array
                        (
                            [id] => 203
                            [case] => first-letter
                            [*] => User profile talk
                            [canonical] => User profile talk
                        )

                    [310] => Array
                        (
                            [id] => 310
                            [case] => first-letter
                            [*] => Shared
                            [canonical] => Shared
                        )

                    [311] => Array
                        (
                            [id] => 311
                            [case] => first-letter
                            [*] => Shared talk
                            [canonical] => Shared talk
                        )

                )

        )

)