MSL NL depth - EPSG:9288

WKT

VERTCS["MSL_NL_depth", 
	VDATUM["Mean_Sea_Level_Netherlands"], 
	PARAMETER["Vertical_Shift", 0.0], 
	PARAMETER["Direction", -1.0], 
	UNIT["Meter", 1.0]]

WKT2

VERTCRS["MSL_NL_depth", 
	VDATUM["Mean_Sea_Level_Netherlands"], 
	CS[vertical, 1], 
	AXIS["Gravity-related height (H)", down, 
		LENGTHUNIT["Meter", 1.0]], 
	ID["EPSG", "9288"]]

Data from @esri/proj-codes

{
  "wkid": 9288,
  "latestWkid": 9288,
  "macro": "PE_VCS_MSL_NL_DEPTH",
  "name": "MSL_NL_depth",
  "wkt": "VERTCS[\"MSL_NL_depth\",VDATUM[\"Mean_Sea_Level_Netherlands\"],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",-1.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "VERTCRS[\"MSL_NL_depth\",VDATUM[\"Mean_Sea_Level_Netherlands\"],CS[vertical,1],AXIS[\"Gravity-related height (H)\",down,LENGTHUNIT[\"Meter\",1.0]],ID[\"EPSG\",\"9288\"]]",
  "description": "MSL NL depth",
  "authority": "EPSG",
  "version": "9.9(12.9.0)",
  "deprecated": "no",
  "areaname": "Netherlands - offshore",
  "extent": {
    "slat": 51.44,
    "nlat": 55.77,
    "llon": 2.53,
    "rlon": 6.37
  }
}