MGI Austria GK M34 - EPSG:31259

WKT

PROJCS["MGI_Austria_GK_M34", 
	GEOGCS["GCS_MGI", 
		DATUM["D_MGI", 
			SPHEROID["Bessel_1841", 6377397.155, 299.1528128]], 
		PRIMEM["Greenwich", 0.0], 
		UNIT["Degree", 0.0174532925199433]], 
	PROJECTION["Transverse_Mercator"], 
	PARAMETER["False_Easting", 750000.0], 
	PARAMETER["False_Northing", -5000000.0], 
	PARAMETER["Central_Meridian", 16.33333333333334], 
	PARAMETER["Scale_Factor", 1.0], 
	PARAMETER["Latitude_Of_Origin", 0.0], 
	UNIT["Meter", 1.0]]

WKT2

PROJCRS["MGI_Austria_GK_M34", 
	BASEGEOGCRS["GCS_MGI", 
		DATUM["D_MGI", 
			ELLIPSOID["Bessel_1841", 6377397.155, 299.1528128]], 
		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", 750000.0], 
		PARAMETER["False_Northing", -5000000.0], 
		PARAMETER["Central_Meridian", 16.33333333333334], 
		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", "31259"]]

Data from @esri/proj-codes

{
  "wkid": 31259,
  "latestWkid": 31259,
  "gcsWkid": 4312,
  "macro": "PE_PCS_MGI_AUSTRIA_GK_M34",
  "name": "MGI_Austria_GK_M34",
  "wkt": "PROJCS[\"MGI_Austria_GK_M34\",GEOGCS[\"GCS_MGI\",DATUM[\"D_MGI\",SPHEROID[\"Bessel_1841\",6377397.155,299.1528128]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]],PROJECTION[\"Transverse_Mercator\"],PARAMETER[\"False_Easting\",750000.0],PARAMETER[\"False_Northing\",-5000000.0],PARAMETER[\"Central_Meridian\",16.33333333333334],PARAMETER[\"Scale_Factor\",1.0],PARAMETER[\"Latitude_Of_Origin\",0.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "PROJCRS[\"MGI_Austria_GK_M34\",BASEGEOGCRS[\"GCS_MGI\",DATUM[\"D_MGI\",ELLIPSOID[\"Bessel_1841\",6377397.155,299.1528128]],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\",750000.0],PARAMETER[\"False_Northing\",-5000000.0],PARAMETER[\"Central_Meridian\",16.33333333333334],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\",\"31259\"]]",
  "description": "MGI Austria GK M34",
  "authority": "EPSG",
  "version": "6.12(9.3.0.0)",
  "deprecated": "no",
  "areaname": "Austria - east of 14~50'E",
  "extent": {
    "slat": 46.56,
    "nlat": 49.02,
    "llon": 14.83,
    "rlon": 17.17
  }
}