EPSG:9929 - DB_REF2003 zone 3

{
  "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
  "type": "CompoundCRS",
  "name": "DB_REF2003 zone 3",
  "components": [
    {
      "type": "ProjectedCRS",
      "name": "DB_REF / 3-degree Gauss-Kruger zone 3 (E-N)",
      "base_crs": {
        "name": "DB_REF",
        "datum": {
          "type": "GeodeticReferenceFrame",
          "name": "Deutsche Bahn Reference System",
          "ellipsoid": {
            "name": "Bessel 1841",
            "semi_major_axis": 6377397.155,
            "inverse_flattening": 299.1528128
          }
        },
        "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": 5681
        }
      },
      "conversion": {
        "name": "3-degree Gauss-Kruger zone 3",
        "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": 9,
            "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": 3500000,
            "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": "GNTRANS height",
      "datum": {
        "type": "VerticalReferenceFrame",
        "name": "GNTRANS"
      },
      "coordinate_system": {
        "subtype": "vertical",
        "axis": [
          {
            "name": "Gravity-related height",
            "abbreviation": "H",
            "direction": "up",
            "unit": "metre"
          }
        ]
      }
    }
  ],
  "scope": "Engineering survey and topographic mapping for railway applications.",
  "area": "Germany - onshore between 7°30'E and 10°30'E.",
  "bbox": {
    "south_latitude": 47.27,
    "west_longitude": 7.5,
    "north_latitude": 55.09,
    "east_longitude": 10.51
  },
  "id": {
    "authority": "EPSG",
    "code": 9929
  }
}

{'crs_wkt': 'COMPOUNDCRS["DB_REF2003 zone 3",PROJCRS["DB_REF / 3-degree '
            'Gauss-Kruger zone 3 (E-N)",BASEGEOGCRS["DB_REF",DATUM["Deutsche '
            'Bahn Reference System",ELLIPSOID["Bessel '
            '1841",6377397.155,299.1528128,LENGTHUNIT["metre",1]]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],ID["EPSG",5681]],CONVERSION["3-degree '
            'Gauss-Kruger zone 3",METHOD["Transverse '
            'Mercator",ID["EPSG",9807]],PARAMETER["Latitude of natural '
            'origin",0,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8801]],PARAMETER["Longitude '
            'of natural '
            'origin",9,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8802]],PARAMETER["Scale '
            'factor at natural '
            'origin",1,SCALEUNIT["unity",1],ID["EPSG",8805]],PARAMETER["False '
            'easting",3500000,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["GNTRANS '
            'height",VDATUM["GNTRANS"],CS[vertical,1],AXIS["gravity-related '
            'height (H)",up,LENGTHUNIT["metre",1]]],USAGE[SCOPE["Engineering '
            'survey and topographic mapping for railway '
            'applications."],AREA["Germany - onshore between 7°30\'E and '
            '10°30\'E."],BBOX[47.27,7.5,55.09,10.51]],ID["EPSG",9929]]',
 'false_easting': 3500000.0,
 'false_northing': 0.0,
 'geographic_crs_name': 'DB_REF',
 'geopotential_datum_name': 'GNTRANS',
 'grid_mapping_name': 'transverse_mercator',
 'horizontal_datum_name': 'Deutsche Bahn Reference System',
 'inverse_flattening': 299.1528128,
 'latitude_of_projection_origin': 0.0,
 'longitude_of_central_meridian': 9.0,
 'longitude_of_prime_meridian': 0.0,
 'prime_meridian_name': 'Greenwich',
 'projected_crs_name': 'DB_REF / 3-degree Gauss-Kruger zone 3 (E-N)',
 'reference_ellipsoid_name': 'Bessel 1841',
 'scale_factor_at_central_meridian': 1.0,
 'semi_major_axis': 6377397.155,
 'semi_minor_axis': 6356078.962818189}