Chatham Islands 1979 Map Grid - EPSG:5519

WKT

PROJCS["Chatham_Islands_1979_Map_Grid", 
	GEOGCS["GCS_Chatham_Islands_1979", 
		DATUM["D_Chatham_Islands_1979", 
			SPHEROID["International_1924", 6378388.0, 297.0]], 
		PRIMEM["Greenwich", 0.0], 
		UNIT["Degree", 0.0174532925199433]], 
	PROJECTION["Transverse_Mercator"], 
	PARAMETER["False_Easting", 350000.0], 
	PARAMETER["False_Northing", 650000.0], 
	PARAMETER["Central_Meridian", -176.5], 
	PARAMETER["Scale_Factor", 1.0], 
	PARAMETER["Latitude_Of_Origin", -44.0], 
	UNIT["Meter", 1.0]]

WKT2

PROJCRS["Chatham_Islands_1979_Map_Grid", 
	BASEGEOGCRS["GCS_Chatham_Islands_1979", 
		DATUM["D_Chatham_Islands_1979", 
			ELLIPSOID["International_1924", 6378388.0, 297.0]], 
		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", 350000.0], 
		PARAMETER["False_Northing", 650000.0], 
		PARAMETER["Central_Meridian", -176.5], 
		PARAMETER["Scale_Factor", 1.0], 
		PARAMETER["Latitude_Of_Origin", -44.0]], 
	CS[Cartesian, 2], 
	AXIS["Northing (Y)", north, 
		ORDER[1]], 
	AXIS["Easting (X)", east, 
		ORDER[2]], 
	LENGTHUNIT["Meter", 1.0], 
	ID["EPSG", "5519"]]

Data from @esri/proj-codes

{
  "wkid": 5519,
  "latestWkid": 5519,
  "gcsWkid": 4673,
  "macro": "PE_PCS_CHATHAM_ISLANDS_1979_MAP_GRID",
  "name": "Chatham_Islands_1979_Map_Grid",
  "wkt": "PROJCS[\"Chatham_Islands_1979_Map_Grid\",GEOGCS[\"GCS_Chatham_Islands_1979\",DATUM[\"D_Chatham_Islands_1979\",SPHEROID[\"International_1924\",6378388.0,297.0]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]],PROJECTION[\"Transverse_Mercator\"],PARAMETER[\"False_Easting\",350000.0],PARAMETER[\"False_Northing\",650000.0],PARAMETER[\"Central_Meridian\",-176.5],PARAMETER[\"Scale_Factor\",1.0],PARAMETER[\"Latitude_Of_Origin\",-44.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "PROJCRS[\"Chatham_Islands_1979_Map_Grid\",BASEGEOGCRS[\"GCS_Chatham_Islands_1979\",DATUM[\"D_Chatham_Islands_1979\",ELLIPSOID[\"International_1924\",6378388.0,297.0]],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\",350000.0],PARAMETER[\"False_Northing\",650000.0],PARAMETER[\"Central_Meridian\",-176.5],PARAMETER[\"Scale_Factor\",1.0],PARAMETER[\"Latitude_Of_Origin\",-44.0]],CS[Cartesian,2],AXIS[\"Northing (Y)\",north,ORDER[1]],AXIS[\"Easting (X)\",east,ORDER[2]],LENGTHUNIT[\"Meter\",1.0],ID[\"EPSG\",\"5519\"]]",
  "description": "Chatham Islands 1979 Map Grid",
  "authority": "EPSG",
  "version": "7.7.1(10.1.0)",
  "deprecated": "no",
  "areaname": "New Zealand - Chatham Islands group",
  "extent": {
    "slat": -44.64,
    "nlat": -43.3,
    "llon": -177.25,
    "rlon": -175.54
  }
}