Vienna height - EPSG:8881

WKT

VERTCS["Vienna_height", 
	VDATUM["Wiener_Null"], 
	PARAMETER["Vertical_Shift", 0.0], 
	PARAMETER["Direction", 1.0], 
	UNIT["Meter", 1.0]]

WKT2

VERTCRS["Vienna_height", 
	VDATUM["Wiener_Null"], 
	CS[vertical, 1], 
	AXIS["Gravity-related height (H)", up, 
		LENGTHUNIT["Meter", 1.0]], 
	ID["EPSG", "8881"]]

Data from @esri/proj-codes

{
  "wkid": 8881,
  "latestWkid": 8881,
  "macro": "PE_VCS_VIENNA_HT",
  "name": "Vienna_height",
  "wkt": "VERTCS[\"Vienna_height\",VDATUM[\"Wiener_Null\"],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",1.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "VERTCRS[\"Vienna_height\",VDATUM[\"Wiener_Null\"],CS[vertical,1],AXIS[\"Gravity-related height (H)\",up,LENGTHUNIT[\"Meter\",1.0]],ID[\"EPSG\",\"8881\"]]",
  "description": "Vienna height",
  "authority": "EPSG",
  "version": "9.8.11(12.7.0)",
  "deprecated": "no",
  "areaname": "Austria - Vienna",
  "extent": {
    "slat": 48.12,
    "nlat": 48.34,
    "llon": 16.18,
    "rlon": 16.59
  }
}