California SRS Epoch 2017.50 (NAD83) - ESRI:115844

WKT

VERTCS["California_SRS_Epoch_2017.50_(NAD83)", 
	DATUM["California_SRS_Epoch_2017.50_(NAD83)", 
		SPHEROID["GRS_1980", 6378137.0, 298.257222101]], 
	PARAMETER["Vertical_Shift", 0.0], 
	PARAMETER["Direction", 1.0], 
	UNIT["Meter", 1.0]]

WKT2

VERTCRS["California_SRS_Epoch_2017.50_(NAD83)", 
	DATUM["California_SRS_Epoch_2017.50_(NAD83)", 
		ELLIPSOID["GRS_1980", 6378137.0, 298.257222101], 
		ANCHOREPOCH[2017.5]], 
	CS[vertical, 1], 
	AXIS["Ellipsoidal height (h)", up, 
		LENGTHUNIT["Meter", 1.0]], 
	ID["Esri", "115844"]]

Data from @esri/proj-codes

{
  "wkid": 115844,
  "latestWkid": 115844,
  "macro": "PE_VCS_CSRS_EPOCH_2017_5_NAD83",
  "name": "California_SRS_Epoch_2017.50_(NAD83)",
  "wkt": "VERTCS[\"California_SRS_Epoch_2017.50_(NAD83)\",DATUM[\"California_SRS_Epoch_2017.50_(NAD83)\",SPHEROID[\"GRS_1980\",6378137.0,298.257222101]],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",1.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "VERTCRS[\"California_SRS_Epoch_2017.50_(NAD83)\",DATUM[\"California_SRS_Epoch_2017.50_(NAD83)\",ELLIPSOID[\"GRS_1980\",6378137.0,298.257222101],ANCHOREPOCH[2017.5]],CS[vertical,1],AXIS[\"Ellipsoidal height (h)\",up,LENGTHUNIT[\"Meter\",1.0]],ID[\"Esri\",\"115844\"]]",
  "description": "California SRS Epoch 2017.50 (NAD83)",
  "authority": "Esri",
  "version": "10.7.0",
  "deprecated": "no",
  "areaname": "USA - California and borders of NV, AZ, OR and MX",
  "extent": {
    "slat": 32.25,
    "nlat": 42.53,
    "llon": -124.45,
    "rlon": -113.6
  }
}