GeoJson saved from geojson-editor

data.geojson

{
  "type": "FeatureCollection",
  "features": [
    {
      "id": "9aea4b3220bc5c9086811e52613880a2",
      "type": "Feature",
      "properties": {},
      "geometry": {
        "coordinates": [
          [
            [
              -6.855468749999886,
              28.690587654250706
            ],
            [
              -38.496093749996874,
              -0.7909904981536044
            ],
            [
              23.55468750000361,
              -12.12526421833148
            ],
            [
              -6.855468749999886,
              28.690587654250706
            ]
          ]
        ],
        "type": "Polygon"
      }
    }
  ]
}