NAD83(CSRS)v6 + CGVD2013a(2010) height - EPSG:9544

WKT

HVCOORDSYS["NAD_1983_CSRS_v6_and_CGVD2013a(2010)_height", 
	GEOGCS["NAD83(CSRS)v6", 
		DATUM["North_American_Datum_of_1983_(CSRS)_version_6", 
			SPHEROID["GRS_1980", 6378137.0, 298.257222101]], 
		PRIMEM["Greenwich", 0.0], 
		UNIT["Degree", 0.0174532925199433]], 
	VERTCS["CGVD2013_CGG2013a_height", 
		VDATUM["Canadian_Geodetic_Vertical_Datum_of_2013_CGG2013a"], 
		PARAMETER["Vertical_Shift", 0.0], 
		PARAMETER["Direction", 1.0], 
		UNIT["Meter", 1.0]]]

WKT2

COMPOUNDCRS["NAD_1983_CSRS_v6_and_CGVD2013a(2010)_height", 
	GEOGCRS["NAD83(CSRS)v6", 
		DATUM["North_American_Datum_of_1983_(CSRS)_version_6", 
			ELLIPSOID["GRS_1980", 6378137.0, 298.257222101], 
			ANCHOREPOCH[2010.0]], 
		PRIMEM["Greenwich", 0.0], 
		CS[ellipsoidal, 2], 
		AXIS["Latitude (lat)", north, 
			ORDER[1]], 
		AXIS["Longitude (lon)", east, 
			ORDER[2]], 
		ANGLEUNIT["Degree", 0.0174532925199433]], 
	VERTCRS["CGVD2013_CGG2013a_height", 
		VDATUM["Canadian_Geodetic_Vertical_Datum_of_2013_CGG2013a", 
			ANCHOREPOCH[2010.0]], 
		CS[vertical, 1], 
		AXIS["Gravity-related height (H)", up, 
			LENGTHUNIT["Meter", 1.0]]], 
	ID["EPSG", "9544"]]

Data from @esri/proj-codes

{
  "wkid": 9544,
  "latestWkid": 9544,
  "pcsWkid": 0,
  "gcsWkid": 8252,
  "vcsWkid": 9245,
  "macro": "PE_HVC_NAD83CSRSV6_CGVD2013A2010_HEIGHT",
  "name": "NAD_1983_CSRS_v6_and_CGVD2013a(2010)_height",
  "wkt": "HVCOORDSYS[\"NAD_1983_CSRS_v6_and_CGVD2013a(2010)_height\",GEOGCS[\"NAD83(CSRS)v6\",DATUM[\"North_American_Datum_of_1983_(CSRS)_version_6\",SPHEROID[\"GRS_1980\",6378137.0,298.257222101]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]],VERTCS[\"CGVD2013_CGG2013a_height\",VDATUM[\"Canadian_Geodetic_Vertical_Datum_of_2013_CGG2013a\"],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",1.0],UNIT[\"Meter\",1.0]]]",
  "wkt2": "COMPOUNDCRS[\"NAD_1983_CSRS_v6_and_CGVD2013a(2010)_height\",GEOGCRS[\"NAD83(CSRS)v6\",DATUM[\"North_American_Datum_of_1983_(CSRS)_version_6\",ELLIPSOID[\"GRS_1980\",6378137.0,298.257222101],ANCHOREPOCH[2010.0]],PRIMEM[\"Greenwich\",0.0],CS[ellipsoidal,2],AXIS[\"Latitude (lat)\",north,ORDER[1]],AXIS[\"Longitude (lon)\",east,ORDER[2]],ANGLEUNIT[\"Degree\",0.0174532925199433]],VERTCRS[\"CGVD2013_CGG2013a_height\",VDATUM[\"Canadian_Geodetic_Vertical_Datum_of_2013_CGG2013a\",ANCHOREPOCH[2010.0]],CS[vertical,1],AXIS[\"Gravity-related height (H)\",up,LENGTHUNIT[\"Meter\",1.0]]],ID[\"EPSG\",\"9544\"]]",
  "description": "NAD83(CSRS)v6 + CGVD2013a(2010) height",
  "authority": "EPSG",
  "version": "10.013(13.2.0)",
  "deprecated": "no",
  "areaname": "Canada",
  "extent": {
    "slat": 38.21,
    "nlat": 86.46,
    "llon": -141.01,
    "rlon": -40.73
  }
}