SLVD height - EPSG:5237

WKT

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

WKT2

VERTCRS["SLVD_height", 
	VDATUM["Sri_Lanka_Vertical_Datum"], 
	CS[vertical, 1], 
	AXIS["Gravity-related height (H)", up, 
		LENGTHUNIT["Meter", 1.0]], 
	ID["EPSG", "5237"]]

Data from @esri/proj-codes

{
  "wkid": 5237,
  "latestWkid": 5237,
  "macro": "PE_VCS_SLVD_HT",
  "name": "SLVD_height",
  "wkt": "VERTCS[\"SLVD_height\",VDATUM[\"Sri_Lanka_Vertical_Datum\"],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",1.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "VERTCRS[\"SLVD_height\",VDATUM[\"Sri_Lanka_Vertical_Datum\"],CS[vertical,1],AXIS[\"Gravity-related height (H)\",up,LENGTHUNIT[\"Meter\",1.0]],ID[\"EPSG\",\"5237\"]]",
  "description": "SLVD height",
  "authority": "EPSG",
  "version": "7.5.9(10.1.0)",
  "deprecated": "no",
  "areaname": "Sri Lanka - onshore",
  "extent": {
    "slat": 5.86,
    "nlat": 9.88,
    "llon": 79.64,
    "rlon": 81.95
  }
}