NAD 1983 (CSRS) v6 UTM Zone 21N - ESRI:103698

WKT

PROJCS["NAD_1983_(CSRS)_v6_UTM_Zone_21N", 
	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]], 
	PROJECTION["Transverse_Mercator"], 
	PARAMETER["False_Easting", 500000.0], 
	PARAMETER["False_Northing", 0.0], 
	PARAMETER["Central_Meridian", -57.0], 
	PARAMETER["Scale_Factor", 0.9996], 
	PARAMETER["Latitude_Of_Origin", 0.0], 
	UNIT["Meter", 1.0]]

WKT2

PROJCRS["NAD_1983_(CSRS)_v6_UTM_Zone_21N", 
	BASEGEOGCRS["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]], 
	CONVERSION["Transverse_Mercator", 
		METHOD["Transverse_Mercator"], 
		PARAMETER["False_Easting", 500000.0], 
		PARAMETER["False_Northing", 0.0], 
		PARAMETER["Central_Meridian", -57.0], 
		PARAMETER["Scale_Factor", 0.9996], 
		PARAMETER["Latitude_Of_Origin", 0.0]], 
	CS[Cartesian, 2], 
	AXIS["Easting (X)", east, 
		ORDER[1]], 
	AXIS["Northing (Y)", north, 
		ORDER[2]], 
	LENGTHUNIT["Meter", 1.0], 
	ID["Esri", "22621"]]

Data from @esri/proj-codes

{
  "wkid": 103698,
  "latestWkid": 22621,
  "gcsWkid": 8252,
  "macro": "PE_PCS_NAD_1983_CSRS_V6_UTM_21N",
  "name": "NAD_1983_(CSRS)_v6_UTM_Zone_21N",
  "wkt": "PROJCS[\"NAD_1983_(CSRS)_v6_UTM_Zone_21N\",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]],PROJECTION[\"Transverse_Mercator\"],PARAMETER[\"False_Easting\",500000.0],PARAMETER[\"False_Northing\",0.0],PARAMETER[\"Central_Meridian\",-57.0],PARAMETER[\"Scale_Factor\",0.9996],PARAMETER[\"Latitude_Of_Origin\",0.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "PROJCRS[\"NAD_1983_(CSRS)_v6_UTM_Zone_21N\",BASEGEOGCRS[\"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]],CONVERSION[\"Transverse_Mercator\",METHOD[\"Transverse_Mercator\"],PARAMETER[\"False_Easting\",500000.0],PARAMETER[\"False_Northing\",0.0],PARAMETER[\"Central_Meridian\",-57.0],PARAMETER[\"Scale_Factor\",0.9996],PARAMETER[\"Latitude_Of_Origin\",0.0]],CS[Cartesian,2],AXIS[\"Easting (X)\",east,ORDER[1]],AXIS[\"Northing (Y)\",north,ORDER[2]],LENGTHUNIT[\"Meter\",1.0],ID[\"Esri\",\"22621\"]]",
  "description": "NAD 1983 (CSRS) v6 UTM Zone 21N",
  "authority": "Esri",
  "version": "10.7.1",
  "deprecated": "codechange",
  "areaname": "Canada - 60~W to 54~W",
  "extent": {
    "slat": 38.56,
    "nlat": 84,
    "llon": -60,
    "rlon": -54
  }
}