SHVD2015 height - EPSG:7890

WKT

VERTCS["SHVD2015_height", 
	VDATUM["St_Helena_Vertical_Datum_2015"], 
	PARAMETER["Vertical_Shift", 0.0], 
	PARAMETER["Direction", 1.0], 
	UNIT["Meter", 1.0]]

WKT2

VERTCRS["SHVD2015_height", 
	VDATUM["St_Helena_Vertical_Datum_2015"], 
	CS[vertical, 1], 
	AXIS["Gravity-related height (H)", up, 
		LENGTHUNIT["Meter", 1.0]], 
	ID["EPSG", "7890"]]

Data from @esri/proj-codes

{
  "wkid": 7890,
  "latestWkid": 7890,
  "macro": "PE_VCS_SHVD2015_HT",
  "name": "SHVD2015_height",
  "wkt": "VERTCS[\"SHVD2015_height\",VDATUM[\"St_Helena_Vertical_Datum_2015\"],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",1.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "VERTCRS[\"SHVD2015_height\",VDATUM[\"St_Helena_Vertical_Datum_2015\"],CS[vertical,1],AXIS[\"Gravity-related height (H)\",up,LENGTHUNIT[\"Meter\",1.0]],ID[\"EPSG\",\"7890\"]]",
  "description": "SHVD2015 height",
  "authority": "EPSG",
  "version": "9.0(10.6.0)",
  "deprecated": "no",
  "areaname": "St Helena - St Helena Island",
  "extent": {
    "slat": -16.08,
    "nlat": -15.85,
    "llon": -5.85,
    "rlon": -5.59
  }
}