You are looking at the HTML representation of the JSON 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 JSON format, set format=json.
See the complete documentation, or API help for more information.
{
    "query": {
        "namespaces": {
            "-2": {
                "id": -2,
                "case": "first-letter",
                "*": "Medio",
                "canonical": "Media"
            },
            "-1": {
                "id": -1,
                "case": "first-letter",
                "*": "Especial",
                "canonical": "Special"
            },
            "0": {
                "id": 0,
                "case": "first-letter",
                "*": "",
                "content": ""
            },
            "1": {
                "id": 1,
                "case": "first-letter",
                "*": "Discusi\u00f3n",
                "subpages": "",
                "canonical": "Talk"
            },
            "2": {
                "id": 2,
                "case": "first-letter",
                "*": "Usuario",
                "subpages": "",
                "canonical": "User"
            },
            "3": {
                "id": 3,
                "case": "first-letter",
                "*": "Usuario discusi\u00f3n",
                "subpages": "",
                "canonical": "User talk"
            },
            "4": {
                "id": 4,
                "case": "first-letter",
                "*": "Wiki Euraxess",
                "subpages": "",
                "canonical": "Project"
            },
            "5": {
                "id": 5,
                "case": "first-letter",
                "*": "Wiki Euraxess discusi\u00f3n",
                "subpages": "",
                "canonical": "Project talk"
            },
            "6": {
                "id": 6,
                "case": "first-letter",
                "*": "Archivo",
                "canonical": "File"
            },
            "7": {
                "id": 7,
                "case": "first-letter",
                "*": "Archivo discusi\u00f3n",
                "subpages": "",
                "canonical": "File talk"
            },
            "8": {
                "id": 8,
                "case": "first-letter",
                "*": "MediaWiki",
                "subpages": "",
                "canonical": "MediaWiki"
            },
            "9": {
                "id": 9,
                "case": "first-letter",
                "*": "MediaWiki discusi\u00f3n",
                "subpages": "",
                "canonical": "MediaWiki talk"
            },
            "10": {
                "id": 10,
                "case": "first-letter",
                "*": "Plantilla",
                "canonical": "Template"
            },
            "11": {
                "id": 11,
                "case": "first-letter",
                "*": "Plantilla discusi\u00f3n",
                "subpages": "",
                "canonical": "Template talk"
            },
            "12": {
                "id": 12,
                "case": "first-letter",
                "*": "Ayuda",
                "subpages": "",
                "canonical": "Help"
            },
            "13": {
                "id": 13,
                "case": "first-letter",
                "*": "Ayuda discusi\u00f3n",
                "subpages": "",
                "canonical": "Help talk"
            },
            "14": {
                "id": 14,
                "case": "first-letter",
                "*": "Categor\u00eda",
                "canonical": "Category"
            },
            "15": {
                "id": 15,
                "case": "first-letter",
                "*": "Categor\u00eda discusi\u00f3n",
                "subpages": "",
                "canonical": "Category talk"
            }
        }
    }
}