EPSG:6893 - WGS 84 / World Mercator + EGM2008 height

{
  "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
  "type": "CompoundCRS",
  "name": "WGS 84 / World Mercator + EGM2008 height",
  "components": [
    {
      "type": "ProjectedCRS",
      "name": "WGS 84 / World Mercator",
      "base_crs": {
        "name": "WGS 84",
        "datum_ensemble": {
          "name": "World Geodetic System 1984 ensemble",
          "members": [
            {
              "name": "World Geodetic System 1984 (Transit)",
              "id": {
                "authority": "EPSG",
                "code": 1166
              }
            },
            {
              "name": "World Geodetic System 1984 (G730)",
              "id": {
                "authority": "EPSG",
                "code": 1152
              }
            },
            {
              "name": "World Geodetic System 1984 (G873)",
              "id": {
                "authority": "EPSG",
                "code": 1153
              }
            },
            {
              "name": "World Geodetic System 1984 (G1150)",
              "id": {
                "authority": "EPSG",
                "code": 1154
              }
            },
            {
              "name": "World Geodetic System 1984 (G1674)",
              "id": {
                "authority": "EPSG",
                "code": 1155
              }
            },
            {
              "name": "World Geodetic System 1984 (G1762)",
              "id": {
                "authority": "EPSG",
                "code": 1156
              }
            },
            {
              "name": "World Geodetic System 1984 (G2139)",
              "id": {
                "authority": "EPSG",
                "code": 1309
              }
            },
            {
              "name": "World Geodetic System 1984 (G2296)",
              "id": {
                "authority": "EPSG",
                "code": 1383
              }
            }
          ],
          "ellipsoid": {
            "name": "WGS 84",
            "semi_major_axis": 6378137,
            "inverse_flattening": 298.257223563
          },
          "accuracy": "2.0",
          "id": {
            "authority": "EPSG",
            "code": 6326
          }
        },
        "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": 4326
        }
      },
      "conversion": {
        "name": "World Mercator",
        "method": {
          "name": "Mercator (variant A)",
          "id": {
            "authority": "EPSG",
            "code": 9804
          }
        },
        "parameters": [
          {
            "name": "Latitude of natural origin",
            "value": 0,
            "unit": "degree",
            "id": {
              "authority": "EPSG",
              "code": 8801
            }
          },
          {
            "name": "Longitude of natural origin",
            "value": 0,
            "unit": "degree",
            "id": {
              "authority": "EPSG",
              "code": 8802
            }
          },
          {
            "name": "Scale factor at natural origin",
            "value": 1,
            "unit": "unity",
            "id": {
              "authority": "EPSG",
              "code": 8805
            }
          },
          {
            "name": "False easting",
            "value": 0,
            "unit": "metre",
            "id": {
              "authority": "EPSG",
              "code": 8806
            }
          },
          {
            "name": "False northing",
            "value": 0,
            "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": "EGM2008 height",
      "datum": {
        "type": "VerticalReferenceFrame",
        "name": "EGM2008 geoid"
      },
      "coordinate_system": {
        "subtype": "vertical",
        "axis": [
          {
            "name": "Gravity-related height",
            "abbreviation": "H",
            "direction": "up",
            "unit": "metre"
          }
        ]
      }
    }
  ],
  "scope": "Engineering design concept visualisation.",
  "area": "World.",
  "bbox": {
    "south_latitude": -90,
    "west_longitude": -180,
    "north_latitude": 90,
    "east_longitude": 180
  },
  "id": {
    "authority": "EPSG",
    "code": 6893
  }
}

{'crs_wkt': 'COMPOUNDCRS["WGS 84 / World Mercator + EGM2008 '
            'height",PROJCRS["WGS 84 / World Mercator",BASEGEOGCRS["WGS '
            '84",ENSEMBLE["World Geodetic System 1984 ensemble",MEMBER["World '
            'Geodetic System 1984 (Transit)"],MEMBER["World Geodetic System '
            '1984 (G730)"],MEMBER["World Geodetic System 1984 '
            '(G873)"],MEMBER["World Geodetic System 1984 '
            '(G1150)"],MEMBER["World Geodetic System 1984 '
            '(G1674)"],MEMBER["World Geodetic System 1984 '
            '(G1762)"],MEMBER["World Geodetic System 1984 '
            '(G2139)"],MEMBER["World Geodetic System 1984 '
            '(G2296)"],ELLIPSOID["WGS '
            '84",6378137,298.257223563,LENGTHUNIT["metre",1]],ENSEMBLEACCURACY[2.0]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],ID["EPSG",4326]],CONVERSION["World '
            'Mercator",METHOD["Mercator (variant '
            'A)",ID["EPSG",9804]],PARAMETER["Latitude of natural '
            'origin",0,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8801]],PARAMETER["Longitude '
            'of natural '
            'origin",0,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8802]],PARAMETER["Scale '
            'factor at natural '
            'origin",1,SCALEUNIT["unity",1],ID["EPSG",8805]],PARAMETER["False '
            'easting",0,LENGTHUNIT["metre",1],ID["EPSG",8806]],PARAMETER["False '
            'northing",0,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["EGM2008 '
            'height",VDATUM["EGM2008 '
            'geoid"],CS[vertical,1],AXIS["gravity-related height '
            '(H)",up,LENGTHUNIT["metre",1]]],USAGE[SCOPE["Engineering design '
            'concept '
            'visualisation."],AREA["World."],BBOX[-90,-180,90,180]],ID["EPSG",6893]]',
 'false_easting': 0.0,
 'false_northing': 0.0,
 'geographic_crs_name': 'WGS 84',
 'geopotential_datum_name': 'EGM2008 geoid',
 'grid_mapping_name': 'mercator',
 'horizontal_datum_name': 'World Geodetic System 1984 ensemble',
 'inverse_flattening': 298.257223563,
 'longitude_of_prime_meridian': 0.0,
 'longitude_of_projection_origin': 0.0,
 'prime_meridian_name': 'Greenwich',
 'projected_crs_name': 'WGS 84 / World Mercator',
 'reference_ellipsoid_name': 'WGS 84',
 'scale_factor_at_projection_origin': 1.0,
 'semi_major_axis': 6378137.0,
 'semi_minor_axis': 6356752.314245179,
 'standard_parallel': 0.0}