You are looking at the HTML representation of the RAW 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 RAW format, set format=raw.
See the complete documentation, or API help for more information.
{
    "query": {
        "namespaces": {
            "-2": {
                "id": -2,
                "case": "first-letter",
                "*": "Media",
                "canonical": "Media"
            },
            "-1": {
                "id": -1,
                "case": "first-letter",
                "*": "Specjalna",
                "canonical": "Special"
            },
            "0": {
                "id": 0,
                "case": "first-letter",
                "*": "",
                "content": ""
            },
            "1": {
                "id": 1,
                "case": "first-letter",
                "*": "Dyskusja",
                "subpages": "",
                "canonical": "Talk"
            },
            "2": {
                "id": 2,
                "case": "first-letter",
                "*": "U\u017cytkownik",
                "subpages": "",
                "canonical": "User"
            },
            "3": {
                "id": 3,
                "case": "first-letter",
                "*": "Dyskusja u\u017cytkownika",
                "subpages": "",
                "canonical": "User talk"
            },
            "4": {
                "id": 4,
                "case": "first-letter",
                "*": "IBR wiki",
                "subpages": "",
                "canonical": "Project"
            },
            "5": {
                "id": 5,
                "case": "first-letter",
                "*": "Dyskusja IBR wiki",
                "subpages": "",
                "canonical": "Project talk"
            },
            "6": {
                "id": 6,
                "case": "first-letter",
                "*": "Plik",
                "canonical": "File"
            },
            "7": {
                "id": 7,
                "case": "first-letter",
                "*": "Dyskusja pliku",
                "subpages": "",
                "canonical": "File talk"
            },
            "8": {
                "id": 8,
                "case": "first-letter",
                "*": "MediaWiki",
                "subpages": "",
                "canonical": "MediaWiki"
            },
            "9": {
                "id": 9,
                "case": "first-letter",
                "*": "Dyskusja MediaWiki",
                "subpages": "",
                "canonical": "MediaWiki talk"
            },
            "10": {
                "id": 10,
                "case": "first-letter",
                "*": "Szablon",
                "canonical": "Template"
            },
            "11": {
                "id": 11,
                "case": "first-letter",
                "*": "Dyskusja szablonu",
                "subpages": "",
                "canonical": "Template talk"
            },
            "12": {
                "id": 12,
                "case": "first-letter",
                "*": "Pomoc",
                "subpages": "",
                "canonical": "Help"
            },
            "13": {
                "id": 13,
                "case": "first-letter",
                "*": "Dyskusja pomocy",
                "subpages": "",
                "canonical": "Help talk"
            },
            "14": {
                "id": 14,
                "case": "first-letter",
                "*": "Kategoria",
                "canonical": "Category"
            },
            "15": {
                "id": 15,
                "case": "first-letter",
                "*": "Dyskusja kategorii",
                "subpages": "",
                "canonical": "Category talk"
            },
            "_element": "ns"
        }
    }
}