Australian Antarctic 1998 - ESRI:115703

WKT

VERTCS["Australian_Antarctic_1998", 
	DATUM["D_Australian_Antarctic_1998", 
		SPHEROID["GRS_1980", 6378137.0, 298.257222101]], 
	PARAMETER["Vertical_Shift", 0.0], 
	PARAMETER["Direction", 1.0], 
	UNIT["Meter", 1.0]]

WKT2

VERTCRS["Australian_Antarctic_1998", 
	DATUM["D_Australian_Antarctic_1998", 
		ELLIPSOID["GRS_1980", 6378137.0, 298.257222101]], 
	CS[vertical, 1], 
	AXIS["Ellipsoidal height (h)", up, 
		LENGTHUNIT["Meter", 1.0]], 
	ID["Esri", "115703"]]

Data from @esri/proj-codes

{
  "wkid": 115703,
  "latestWkid": 115703,
  "macro": "PE_VCS_AUSTRALIAN_ANTARCTIC_1998",
  "name": "Australian_Antarctic_1998",
  "wkt": "VERTCS[\"Australian_Antarctic_1998\",DATUM[\"D_Australian_Antarctic_1998\",SPHEROID[\"GRS_1980\",6378137.0,298.257222101]],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",1.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "VERTCRS[\"Australian_Antarctic_1998\",DATUM[\"D_Australian_Antarctic_1998\",ELLIPSOID[\"GRS_1980\",6378137.0,298.257222101]],CS[vertical,1],AXIS[\"Ellipsoidal height (h)\",up,LENGTHUNIT[\"Meter\",1.0]],ID[\"Esri\",\"115703\"]]",
  "description": "Australian Antarctic 1998",
  "authority": "Esri",
  "version": "10.4.0",
  "deprecated": "no",
  "areaname": "Antarctica - Australian sector",
  "extent": {
    "slat": -90,
    "nlat": -60,
    "llon": 45,
    "rlon": 160
  }
}