linestrings are rendered by the flat earth society

[mlc]

I entered the following GeoJSON in geojson.io:

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "geometry": {
        "type": "LineString",
        "coordinates": [
          [52.9548, 16.41254],
          [-112.85016, 50.8102]
        ]
      },
      "properties": {}
    }
  ]
}

This is a long arc, and on a spherical or nearly-spherical surface, one would expect the great circle route to bend towards the poles, as shown e.g. in this render from gcmap.com:

However, geojson.io renders the path as a "straight line" in the Mercator projection, which is not a straight line on the surface of the earth:

It would be better if geojson.io respected the curvature of the earth, or at a minimum had the option to do so somehow.