Martinique 1950 - EPSG:5794

WKT

VERTCS["Martinique_1955", 
	VDATUM["Martinique_1955"], 
	PARAMETER["Vertical_Shift", 0.0], 
	PARAMETER["Direction", 1.0], 
	UNIT["Meter", 1.0]]

WKT2

VERTCRS["Martinique_1955", 
	VDATUM["Martinique_1955"], 
	CS[vertical, 1], 
	AXIS["Gravity-related height (H)", up, 
		LENGTHUNIT["Meter", 1.0]], 
	ID["EPSG", "5794"]]

Data from @esri/proj-codes

{
  "wkid": 5794,
  "latestWkid": 5794,
  "macro": "PE_VCS_MARTINIQUE_1955",
  "name": "Martinique_1955",
  "wkt": "VERTCS[\"Martinique_1955\",VDATUM[\"Martinique_1955\"],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",1.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "VERTCRS[\"Martinique_1955\",VDATUM[\"Martinique_1955\"],CS[vertical,1],AXIS[\"Gravity-related height (H)\",up,LENGTHUNIT[\"Meter\",1.0]],ID[\"EPSG\",\"5794\"]]",
  "description": "Martinique 1950",
  "authority": "EPSG",
  "version": "6.15(9.3.0.0)",
  "deprecated": "no",
  "areaname": "Martinique - onshore",
  "extent": {
    "slat": 14.35,
    "nlat": 14.93,
    "llon": -61.29,
    "rlon": -60.76
  }
}