EPSG:7843

GEOGCRS["GDA2020",
    DATUM["Geocentric Datum of Australia 2020",
        ELLIPSOID["GRS 1980",6378137,298.257222101,
            LENGTHUNIT["metre",1]]],
    PRIMEM["Greenwich",0,
        ANGLEUNIT["degree",0.0174532925199433]],
    CS[ellipsoidal,3],
        AXIS["geodetic latitude (Lat)",north,
            ORDER[1],
            ANGLEUNIT["degree",0.0174532925199433]],
        AXIS["geodetic longitude (Lon)",east,
            ORDER[2],
            ANGLEUNIT["degree",0.0174532925199433]],
        AXIS["ellipsoidal height (h)",up,
            ORDER[3],
            LENGTHUNIT["metre",1]],
    USAGE[
        SCOPE["Geodesy, cadastre, engineering survey, topographic mapping."],
        AREA["Australia including Lord Howe Island, Macquarie Island, Ashmore and Cartier Islands, Christmas Island, Cocos (Keeling) Islands, Norfolk Island. All onshore and offshore."],
        BBOX[-60.55,93.41,-8.47,173.34]],
    ID["EPSG",7843]]

GEOGCS["GDA2020_3D",
    DATUM["GDA2020",
        SPHEROID["GRS_1980",6378137.0,298.257222101]],
    PRIMEM["Greenwich",0.0],
    UNIT["Degree",0.0174532925199433],
    LINUNIT["Meter",1.0]]

proj4.defs("EPSG:7843","+proj=longlat +ellps=GRS80 +no_defs +type=crs");

{
    "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
    "type": "GeographicCRS",
    "name": "GDA2020",
    "datum": {
        "type": "GeodeticReferenceFrame",
        "name": "Geocentric Datum of Australia 2020",
        "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"
            },
            {
                "name": "Ellipsoidal height",
                "abbreviation": "h",
                "direction": "up",
                "unit": "metre"
            }
        ]
    },
    "scope": "Geodesy, cadastre, engineering survey, topographic mapping.",
    "area": "Australia including Lord Howe Island, Macquarie Island, Ashmore and Cartier Islands, Christmas Island, Cocos (Keeling) Islands, Norfolk Island. All onshore and offshore.",
    "bbox": {
        "south_latitude": -60.55,
        "west_longitude": 93.41,
        "north_latitude": -8.47,
        "east_longitude": 173.34
    },
    "id": {
        "authority": "EPSG",
        "code": 7843
    }
}

<?xml version="1.0" encoding="utf-8"?>
<Map srs="+proj=longlat +ellps=GRS80 +no_defs +type=crs">
	<Layer srs="+proj=longlat +ellps=GRS80 +no_defs +type=crs">
	</Layer>
</Map>