Hong Kong Principal Datum - EPSG:5738

WKT

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

WKT2

VERTCRS["Hong_Kong_Principal_Datum", 
	VDATUM["Hong_Kong_Principal_Datum"], 
	CS[vertical, 1], 
	AXIS["Gravity-related height (H)", up, 
		LENGTHUNIT["Meter", 1.0]], 
	ID["EPSG", "5738"]]

Data from @esri/proj-codes

{
  "wkid": 5738,
  "latestWkid": 5738,
  "macro": "PE_VCS_HONG_KONG_PRINCIPAL_DATUM",
  "name": "Hong_Kong_Principal_Datum",
  "wkt": "VERTCS[\"Hong_Kong_Principal_Datum\",VDATUM[\"Hong_Kong_Principal_Datum\"],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",1.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "VERTCRS[\"Hong_Kong_Principal_Datum\",VDATUM[\"Hong_Kong_Principal_Datum\"],CS[vertical,1],AXIS[\"Gravity-related height (H)\",up,LENGTHUNIT[\"Meter\",1.0]],ID[\"EPSG\",\"5738\"]]",
  "description": "Hong Kong Principal Datum",
  "authority": "EPSG",
  "version": "6.15(9.3.0.0)",
  "deprecated": "no",
  "areaname": "Hong Kong - onshore",
  "extent": {
    "slat": 22.19,
    "nlat": 22.56,
    "llon": 113.82,
    "rlon": 114.39
  }
}