Kumul 34 height - EPSG:7651

WKT

VERTCS["Kumul_34_(height)", 
	VDATUM["Kumul_34"], 
	PARAMETER["Vertical_Shift", 0.0], 
	PARAMETER["Direction", 1.0], 
	UNIT["Meter", 1.0]]

WKT2

VERTCRS["Kumul_34_(height)", 
	VDATUM["Kumul_34"], 
	CS[vertical, 1], 
	AXIS["Gravity-related height (H)", up, 
		LENGTHUNIT["Meter", 1.0]], 
	ID["EPSG", "7651"]]

Data from @esri/proj-codes

{
  "wkid": 7651,
  "latestWkid": 7651,
  "macro": "PE_VCS_KUMUL_34_HT",
  "name": "Kumul_34_(height)",
  "wkt": "VERTCS[\"Kumul_34_(height)\",VDATUM[\"Kumul_34\"],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",1.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "VERTCRS[\"Kumul_34_(height)\",VDATUM[\"Kumul_34\"],CS[vertical,1],AXIS[\"Gravity-related height (H)\",up,LENGTHUNIT[\"Meter\",1.0]],ID[\"EPSG\",\"7651\"]]",
  "description": "Kumul 34 height",
  "authority": "EPSG",
  "version": "8.8(10.5.0)",
  "deprecated": "no",
  "areaname": "Papua New Guinea - PFTB",
  "extent": {
    "slat": -8.28,
    "nlat": -5.59,
    "llon": 142.24,
    "rlon": 144.75
  }
}