KKJ Finland Zone 0 - EPSG:3386

WKT

PROJCS["KKJ_Finland_Zone_0", 
	GEOGCS["GCS_KKJ", 
		DATUM["D_KKJ", 
			SPHEROID["International_1924", 6378388.0, 297.0]], 
		PRIMEM["Greenwich", 0.0], 
		UNIT["Degree", 0.0174532925199433]], 
	PROJECTION["Gauss_Kruger"], 
	PARAMETER["False_Easting", 500000.0], 
	PARAMETER["False_Northing", 0.0], 
	PARAMETER["Central_Meridian", 18.0], 
	PARAMETER["Scale_Factor", 1.0], 
	PARAMETER["Latitude_Of_Origin", 0.0], 
	UNIT["Meter", 1.0]]

WKT2

PROJCRS["KKJ_Finland_Zone_0", 
	BASEGEOGCRS["GCS_KKJ", 
		DATUM["D_KKJ", 
			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["Gauss_Kruger", 
		METHOD["Gauss_Kruger"], 
		PARAMETER["False_Easting", 500000.0], 
		PARAMETER["False_Northing", 0.0], 
		PARAMETER["Central_Meridian", 18.0], 
		PARAMETER["Scale_Factor", 1.0], 
		PARAMETER["Latitude_Of_Origin", 0.0]], 
	CS[Cartesian, 2], 
	AXIS["Northing (Y)", north, 
		ORDER[1]], 
	AXIS["Easting (X)", east, 
		ORDER[2]], 
	LENGTHUNIT["Meter", 1.0], 
	ID["EPSG", "3386"]]

Data from @esri/proj-codes

{
  "wkid": 3386,
  "latestWkid": 3386,
  "gcsWkid": 4123,
  "macro": "PE_PCS_KKJ_FINLAND_0",
  "name": "KKJ_Finland_Zone_0",
  "wkt": "PROJCS[\"KKJ_Finland_Zone_0\",GEOGCS[\"GCS_KKJ\",DATUM[\"D_KKJ\",SPHEROID[\"International_1924\",6378388.0,297.0]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]],PROJECTION[\"Gauss_Kruger\"],PARAMETER[\"False_Easting\",500000.0],PARAMETER[\"False_Northing\",0.0],PARAMETER[\"Central_Meridian\",18.0],PARAMETER[\"Scale_Factor\",1.0],PARAMETER[\"Latitude_Of_Origin\",0.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "PROJCRS[\"KKJ_Finland_Zone_0\",BASEGEOGCRS[\"GCS_KKJ\",DATUM[\"D_KKJ\",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[\"Gauss_Kruger\",METHOD[\"Gauss_Kruger\"],PARAMETER[\"False_Easting\",500000.0],PARAMETER[\"False_Northing\",0.0],PARAMETER[\"Central_Meridian\",18.0],PARAMETER[\"Scale_Factor\",1.0],PARAMETER[\"Latitude_Of_Origin\",0.0]],CS[Cartesian,2],AXIS[\"Northing (Y)\",north,ORDER[1]],AXIS[\"Easting (X)\",east,ORDER[2]],LENGTHUNIT[\"Meter\",1.0],ID[\"EPSG\",\"3386\"]]",
  "description": "KKJ Finland Zone 0",
  "authority": "EPSG",
  "version": "7.8(9.3.0.0)",
  "deprecated": "no",
  "areaname": "Finland - west of 19.5~E onshore",
  "extent": {
    "slat": 60.08,
    "nlat": 60.34,
    "llon": 19.24,
    "rlon": 19.5
  }
}