Datum 73 Hayford Gauss IPCC - ESRI:102161

WKT

PROJCS["Datum_73_Hayford_Gauss_IPCC", 
	GEOGCS["GCS_Datum_73", 
		DATUM["D_Datum_73", 
			SPHEROID["International_1924", 6378388.0, 297.0]], 
		PRIMEM["Greenwich", 0.0], 
		UNIT["Degree", 0.0174532925199433]], 
	PROJECTION["Transverse_Mercator"], 
	PARAMETER["False_Easting", 180.598], 
	PARAMETER["False_Northing", -86.99], 
	PARAMETER["Central_Meridian", -8.131906111111112], 
	PARAMETER["Scale_Factor", 1.0], 
	PARAMETER["Latitude_Of_Origin", 39.66666666666666], 
	UNIT["Meter", 1.0]]

WKT2

PROJCRS["Datum_73_Hayford_Gauss_IPCC", 
	BASEGEOGCRS["GCS_Datum_73", 
		DATUM["D_Datum_73", 
			ELLIPSOID["International_1924", 6378388.0, 297.0]], 
		PRIMEM["Greenwich", 0.0], 
		CS[ellipsoidal, 2], 
		AXIS["Latitude (lat)", north, 
			ORDER[1]], 
		AXIS["Longitude (lon)", east, 
			ORDER[2]], 
		ANGLEUNIT["Degree", 0.0174532925199433]], 
	CONVERSION["Transverse_Mercator", 
		METHOD["Transverse_Mercator"], 
		PARAMETER["False_Easting", 180.598], 
		PARAMETER["False_Northing", -86.99], 
		PARAMETER["Central_Meridian", -8.131906111111112], 
		PARAMETER["Scale_Factor", 1.0], 
		PARAMETER["Latitude_Of_Origin", 39.66666666666666]], 
	CS[Cartesian, 2], 
	AXIS["Easting (X)", east, 
		ORDER[1]], 
	AXIS["Northing (Y)", north, 
		ORDER[2]], 
	LENGTHUNIT["Meter", 1.0], 
	ID["Esri", "102161"]]

Data from @esri/proj-codes

{
  "wkid": 102161,
  "latestWkid": 102161,
  "gcsWkid": 4274,
  "macro": "PE_PCS_DATUM_73_HAYFORD_GAUSS_IPCC",
  "name": "Datum_73_Hayford_Gauss_IPCC",
  "wkt": "PROJCS[\"Datum_73_Hayford_Gauss_IPCC\",GEOGCS[\"GCS_Datum_73\",DATUM[\"D_Datum_73\",SPHEROID[\"International_1924\",6378388.0,297.0]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]],PROJECTION[\"Transverse_Mercator\"],PARAMETER[\"False_Easting\",180.598],PARAMETER[\"False_Northing\",-86.99],PARAMETER[\"Central_Meridian\",-8.131906111111112],PARAMETER[\"Scale_Factor\",1.0],PARAMETER[\"Latitude_Of_Origin\",39.66666666666666],UNIT[\"Meter\",1.0]]",
  "wkt2": "PROJCRS[\"Datum_73_Hayford_Gauss_IPCC\",BASEGEOGCRS[\"GCS_Datum_73\",DATUM[\"D_Datum_73\",ELLIPSOID[\"International_1924\",6378388.0,297.0]],PRIMEM[\"Greenwich\",0.0],CS[ellipsoidal,2],AXIS[\"Latitude (lat)\",north,ORDER[1]],AXIS[\"Longitude (lon)\",east,ORDER[2]],ANGLEUNIT[\"Degree\",0.0174532925199433]],CONVERSION[\"Transverse_Mercator\",METHOD[\"Transverse_Mercator\"],PARAMETER[\"False_Easting\",180.598],PARAMETER[\"False_Northing\",-86.99],PARAMETER[\"Central_Meridian\",-8.131906111111112],PARAMETER[\"Scale_Factor\",1.0],PARAMETER[\"Latitude_Of_Origin\",39.66666666666666]],CS[Cartesian,2],AXIS[\"Easting (X)\",east,ORDER[1]],AXIS[\"Northing (Y)\",north,ORDER[2]],LENGTHUNIT[\"Meter\",1.0],ID[\"Esri\",\"102161\"]]",
  "description": "Datum 73 Hayford Gauss IPCC",
  "authority": "Esri",
  "version": "8.1.0",
  "deprecated": "no",
  "areaname": "Portugal - mainland - onshore",
  "extent": {
    "slat": 36.95,
    "nlat": 42.16,
    "llon": -9.56,
    "rlon": -6.19
  }
}