EPSG:7956 - SHMG2015 + SHVD2015 height

{
  "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
  "type": "CompoundCRS",
  "name": "SHMG2015 + SHVD2015 height",
  "components": [
    {
      "type": "ProjectedCRS",
      "name": "SHMG2015",
      "base_crs": {
        "name": "SHGD2015",
        "datum": {
          "type": "GeodeticReferenceFrame",
          "name": "St. Helena Geodetic Datum 2015",
          "ellipsoid": {
            "name": "GRS 1980",
            "semi_major_axis": 6378137,
            "inverse_flattening": 298.257222101
          }
        },
        "coordinate_system": {
          "subtype": "ellipsoidal",
          "axis": [
            {
              "name": "Geodetic latitude",
              "abbreviation": "Lat",
              "direction": "north",
              "unit": "degree"
            },
            {
              "name": "Geodetic longitude",
              "abbreviation": "Lon",
              "direction": "east",
              "unit": "degree"
            }
          ]
        },
        "id": {
          "authority": "EPSG",
          "code": 7886
        }
      },
      "conversion": {
        "name": "UTM zone 30S",
        "method": {
          "name": "Transverse Mercator",
          "id": {
            "authority": "EPSG",
            "code": 9807
          }
        },
        "parameters": [
          {
            "name": "Latitude of natural origin",
            "value": 0,
            "unit": "degree",
            "id": {
              "authority": "EPSG",
              "code": 8801
            }
          },
          {
            "name": "Longitude of natural origin",
            "value": -3,
            "unit": "degree",
            "id": {
              "authority": "EPSG",
              "code": 8802
            }
          },
          {
            "name": "Scale factor at natural origin",
            "value": 0.9996,
            "unit": "unity",
            "id": {
              "authority": "EPSG",
              "code": 8805
            }
          },
          {
            "name": "False easting",
            "value": 500000,
            "unit": "metre",
            "id": {
              "authority": "EPSG",
              "code": 8806
            }
          },
          {
            "name": "False northing",
            "value": 10000000,
            "unit": "metre",
            "id": {
              "authority": "EPSG",
              "code": 8807
            }
          }
        ]
      },
      "coordinate_system": {
        "subtype": "Cartesian",
        "axis": [
          {
            "name": "Easting",
            "abbreviation": "E",
            "direction": "east",
            "unit": "metre"
          },
          {
            "name": "Northing",
            "abbreviation": "N",
            "direction": "north",
            "unit": "metre"
          }
        ]
      }
    },
    {
      "type": "VerticalCRS",
      "name": "SHVD2015 height",
      "datum": {
        "type": "VerticalReferenceFrame",
        "name": "St. Helena Vertical Datum 2015"
      },
      "coordinate_system": {
        "subtype": "vertical",
        "axis": [
          {
            "name": "Gravity-related height",
            "abbreviation": "H",
            "direction": "up",
            "unit": "metre"
          }
        ]
      }
    }
  ],
  "scope": "Topographic mapping.",
  "area": "St Helena, Ascension and Tristan da Cunha - St Helena Island - onshore.",
  "bbox": {
    "south_latitude": -16.08,
    "west_longitude": -5.85,
    "north_latitude": -15.85,
    "east_longitude": -5.59
  },
  "id": {
    "authority": "EPSG",
    "code": 7956
  }
}

{'crs_wkt': 'COMPOUNDCRS["SHMG2015 + SHVD2015 '
            'height",PROJCRS["SHMG2015",BASEGEOGCRS["SHGD2015",DATUM["St. '
            'Helena Geodetic Datum 2015",ELLIPSOID["GRS '
            '1980",6378137,298.257222101,LENGTHUNIT["metre",1]]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],ID["EPSG",7886]],CONVERSION["UTM '
            'zone 30S",METHOD["Transverse '
            'Mercator",ID["EPSG",9807]],PARAMETER["Latitude of natural '
            'origin",0,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8801]],PARAMETER["Longitude '
            'of natural '
            'origin",-3,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8802]],PARAMETER["Scale '
            'factor at natural '
            'origin",0.9996,SCALEUNIT["unity",1],ID["EPSG",8805]],PARAMETER["False '
            'easting",500000,LENGTHUNIT["metre",1],ID["EPSG",8806]],PARAMETER["False '
            'northing",10000000,LENGTHUNIT["metre",1],ID["EPSG",8807]]],CS[Cartesian,2],AXIS["(E)",east,ORDER[1],LENGTHUNIT["metre",1]],AXIS["(N)",north,ORDER[2],LENGTHUNIT["metre",1]]],VERTCRS["SHVD2015 '
            'height",VDATUM["St. Helena Vertical Datum '
            '2015"],CS[vertical,1],AXIS["gravity-related height '
            '(H)",up,LENGTHUNIT["metre",1]]],USAGE[SCOPE["Topographic '
            'mapping."],AREA["St Helena, Ascension and Tristan da Cunha - St '
            'Helena Island - '
            'onshore."],BBOX[-16.08,-5.85,-15.85,-5.59]],ID["EPSG",7956]]',
 'false_easting': 500000.0,
 'false_northing': 10000000.0,
 'geographic_crs_name': 'SHGD2015',
 'geopotential_datum_name': 'St. Helena Vertical Datum 2015',
 'grid_mapping_name': 'transverse_mercator',
 'horizontal_datum_name': 'St. Helena Geodetic Datum 2015',
 'inverse_flattening': 298.257222101,
 'latitude_of_projection_origin': 0.0,
 'longitude_of_central_meridian': -3.0,
 'longitude_of_prime_meridian': 0.0,
 'prime_meridian_name': 'Greenwich',
 'projected_crs_name': 'SHMG2015',
 'reference_ellipsoid_name': 'GRS 1980',
 'scale_factor_at_central_meridian': 0.9996,
 'semi_major_axis': 6378137.0,
 'semi_minor_axis': 6356752.314140356}