TWVD 2001 height - EPSG:8904

WKT

VERTCS["TWVD_2001_height", 
	VDATUM["Taiwan_Vertical_Datum_2001"], 
	PARAMETER["Vertical_Shift", 0.0], 
	PARAMETER["Direction", 1.0], 
	UNIT["Meter", 1.0]]

WKT2

VERTCRS["TWVD_2001_height", 
	VDATUM["Taiwan_Vertical_Datum_2001"], 
	CS[vertical, 1], 
	AXIS["Gravity-related height (H)", up, 
		LENGTHUNIT["Meter", 1.0]], 
	ID["EPSG", "8904"]]

Data from @esri/proj-codes

{
  "wkid": 8904,
  "latestWkid": 8904,
  "macro": "PE_VCS_TWVD_2001_HT",
  "name": "TWVD_2001_height",
  "wkt": "VERTCS[\"TWVD_2001_height\",VDATUM[\"Taiwan_Vertical_Datum_2001\"],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",1.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "VERTCRS[\"TWVD_2001_height\",VDATUM[\"Taiwan_Vertical_Datum_2001\"],CS[vertical,1],AXIS[\"Gravity-related height (H)\",up,LENGTHUNIT[\"Meter\",1.0]],ID[\"EPSG\",\"8904\"]]",
  "description": "TWVD 2001 height",
  "authority": "EPSG",
  "version": "9.6.1(10.8.0)",
  "deprecated": "no",
  "areaname": "Taiwan - onshore - mainland",
  "extent": {
    "slat": 21.87,
    "nlat": 25.34,
    "llon": 119.99,
    "rlon": 122.06
  }
}