EPSG:9424 - ETRS89 + ODN height

{
  "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
  "type": "CompoundCRS",
  "name": "ETRS89 + ODN height",
  "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": "ODN height",
      "datum": {
        "type": "VerticalReferenceFrame",
        "name": "Ordnance Datum Newlyn"
      },
      "coordinate_system": {
        "subtype": "vertical",
        "axis": [
          {
            "name": "Gravity-related height",
            "abbreviation": "H",
            "direction": "up",
            "unit": "metre"
          }
        ]
      }
    }
  ],
  "scope": "Spatial referencing.",
  "area": "United Kingdom (UK) - Great Britain onshore - England and Wales - mainland; Scotland - mainland and Inner Hebrides.",
  "bbox": {
    "south_latitude": 49.93,
    "west_longitude": -7.06,
    "north_latitude": 58.71,
    "east_longitude": 1.8
  },
  "id": {
    "authority": "EPSG",
    "code": 9424
  }
}

{'crs_wkt': 'COMPOUNDCRS["ETRS89 + ODN '
            'height",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["ODN '
            'height",VDATUM["Ordnance Datum '
            'Newlyn"],CS[vertical,1],AXIS["gravity-related height '
            '(H)",up,LENGTHUNIT["metre",1]]],USAGE[SCOPE["Spatial '
            'referencing."],AREA["United Kingdom (UK) - Great Britain onshore '
            '- England and Wales - mainland; Scotland - mainland and Inner '
            'Hebrides."],BBOX[49.93,-7.06,58.71,1.8]],ID["EPSG",9424]]',
 'geographic_crs_name': 'ETRS89',
 'geopotential_datum_name': 'Ordnance Datum Newlyn',
 '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}