EPSG:9290 - ETRS89 + MSL NL depth

{
  "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
  "type": "CompoundCRS",
  "name": "ETRS89 + MSL NL depth",
  "components": [
    {
      "type": "GeographicCRS",
      "name": "ETRS89",
      "datum_ensemble": {
        "name": "European Terrestrial Reference System 1989 ensemble",
        "members": [
          {
            "name": "European Terrestrial Reference Frame 1989",
            "id": {
              "authority": "EPSG",
              "code": 1178
            }
          },
          {
            "name": "European Terrestrial Reference Frame 1990",
            "id": {
              "authority": "EPSG",
              "code": 1179
            }
          },
          {
            "name": "European Terrestrial Reference Frame 1991",
            "id": {
              "authority": "EPSG",
              "code": 1180
            }
          },
          {
            "name": "European Terrestrial Reference Frame 1992",
            "id": {
              "authority": "EPSG",
              "code": 1181
            }
          },
          {
            "name": "European Terrestrial Reference Frame 1993",
            "id": {
              "authority": "EPSG",
              "code": 1182
            }
          },
          {
            "name": "European Terrestrial Reference Frame 1994",
            "id": {
              "authority": "EPSG",
              "code": 1183
            }
          },
          {
            "name": "European Terrestrial Reference Frame 1996",
            "id": {
              "authority": "EPSG",
              "code": 1184
            }
          },
          {
            "name": "European Terrestrial Reference Frame 1997",
            "id": {
              "authority": "EPSG",
              "code": 1185
            }
          },
          {
            "name": "European Terrestrial Reference Frame 2000",
            "id": {
              "authority": "EPSG",
              "code": 1186
            }
          },
          {
            "name": "European Terrestrial Reference Frame 2005",
            "id": {
              "authority": "EPSG",
              "code": 1204
            }
          },
          {
            "name": "European Terrestrial Reference Frame 2014",
            "id": {
              "authority": "EPSG",
              "code": 1206
            }
          },
          {
            "name": "European Terrestrial Reference Frame 2020",
            "id": {
              "authority": "EPSG",
              "code": 1382
            }
          }
        ],
        "ellipsoid": {
          "name": "GRS 1980",
          "semi_major_axis": 6378137,
          "inverse_flattening": 298.257222101
        },
        "accuracy": "0.1",
        "id": {
          "authority": "EPSG",
          "code": 6258
        }
      },
      "coordinate_system": {
        "subtype": "ellipsoidal",
        "axis": [
          {
            "name": "Geodetic latitude",
            "abbreviation": "Lat",
            "direction": "north",
            "unit": "degree"
          },
          {
            "name": "Geodetic longitude",
            "abbreviation": "Lon",
            "direction": "east",
            "unit": "degree"
          }
        ]
      }
    },
    {
      "type": "VerticalCRS",
      "name": "MSL NL depth",
      "datum": {
        "type": "VerticalReferenceFrame",
        "name": "Mean Sea Level Netherlands"
      },
      "coordinate_system": {
        "subtype": "vertical",
        "axis": [
          {
            "name": "Depth",
            "abbreviation": "D",
            "direction": "down",
            "unit": "metre"
          }
        ]
      }
    }
  ],
  "scope": "Hydrography, drilling, offshore engineering.",
  "area": "Netherlands - offshore North Sea and nearshore.",
  "bbox": {
    "south_latitude": 51.32,
    "west_longitude": 2.53,
    "north_latitude": 55.77,
    "east_longitude": 7.21
  },
  "id": {
    "authority": "EPSG",
    "code": 9290
  }
}

{'crs_wkt': 'COMPOUNDCRS["ETRS89 + MSL NL '
            'depth",GEOGCRS["ETRS89",ENSEMBLE["European Terrestrial Reference '
            'System 1989 ensemble",MEMBER["European Terrestrial Reference '
            'Frame 1989"],MEMBER["European Terrestrial Reference Frame '
            '1990"],MEMBER["European Terrestrial Reference Frame '
            '1991"],MEMBER["European Terrestrial Reference Frame '
            '1992"],MEMBER["European Terrestrial Reference Frame '
            '1993"],MEMBER["European Terrestrial Reference Frame '
            '1994"],MEMBER["European Terrestrial Reference Frame '
            '1996"],MEMBER["European Terrestrial Reference Frame '
            '1997"],MEMBER["European Terrestrial Reference Frame '
            '2000"],MEMBER["European Terrestrial Reference Frame '
            '2005"],MEMBER["European Terrestrial Reference Frame '
            '2014"],MEMBER["European Terrestrial Reference Frame '
            '2020"],ELLIPSOID["GRS '
            '1980",6378137,298.257222101,LENGTHUNIT["metre",1]],ENSEMBLEACCURACY[0.1]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],CS[ellipsoidal,2],AXIS["geodetic '
            'latitude '
            '(Lat)",north,ORDER[1],ANGLEUNIT["degree",0.0174532925199433]],AXIS["geodetic '
            'longitude '
            '(Lon)",east,ORDER[2],ANGLEUNIT["degree",0.0174532925199433]]],VERTCRS["MSL '
            'NL depth",VDATUM["Mean Sea Level '
            'Netherlands"],CS[vertical,1],AXIS["depth '
            '(D)",down,LENGTHUNIT["metre",1]]],USAGE[SCOPE["Hydrography, '
            'drilling, offshore engineering."],AREA["Netherlands - offshore '
            'North Sea and '
            'nearshore."],BBOX[51.32,2.53,55.77,7.21]],ID["EPSG",9290]]',
 'geographic_crs_name': 'ETRS89',
 'geopotential_datum_name': 'Mean Sea Level Netherlands',
 'grid_mapping_name': 'latitude_longitude',
 'horizontal_datum_name': 'European Terrestrial Reference System 1989 ensemble',
 'inverse_flattening': 298.257222101,
 'longitude_of_prime_meridian': 0.0,
 'prime_meridian_name': 'Greenwich',
 'reference_ellipsoid_name': 'GRS 1980',
 'semi_major_axis': 6378137.0,
 'semi_minor_axis': 6356752.314140356}