Astro DOS 71-4 SHLG71 - EPSG:7877

WKT

PROJCS["Astro_DOS_71_4_SHLG71", 
	GEOGCS["GCS_DOS_71_4", 
		DATUM["D_DOS_71_4", 
			SPHEROID["International_1924", 6378388.0, 297.0]], 
		PRIMEM["Greenwich", 0.0], 
		UNIT["Degree", 0.0174532925199433]], 
	PROJECTION["Transverse_Mercator"], 
	PARAMETER["False_Easting", 300000.0], 
	PARAMETER["False_Northing", 2000000.0], 
	PARAMETER["Central_Meridian", -5.716666666666667], 
	PARAMETER["Scale_Factor", 1.0], 
	PARAMETER["Latitude_Of_Origin", -15.96666666666667], 
	UNIT["Meter", 1.0]]

WKT2

PROJCRS["Astro_DOS_71_4_SHLG71", 
	BASEGEOGCRS["GCS_DOS_71_4", 
		DATUM["D_DOS_71_4", 
			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", 300000.0], 
		PARAMETER["False_Northing", 2000000.0], 
		PARAMETER["Central_Meridian", -5.716666666666667], 
		PARAMETER["Scale_Factor", 1.0], 
		PARAMETER["Latitude_Of_Origin", -15.96666666666667]], 
	CS[Cartesian, 2], 
	AXIS["Easting (X)", east, 
		ORDER[1]], 
	AXIS["Northing (Y)", north, 
		ORDER[2]], 
	LENGTHUNIT["Meter", 1.0], 
	ID["EPSG", "7877"]]

Data from @esri/proj-codes

{
  "wkid": 7877,
  "latestWkid": 7877,
  "gcsWkid": 4710,
  "macro": "PE_PCS_DOS_71_4_SHLG71",
  "name": "Astro_DOS_71_4_SHLG71",
  "wkt": "PROJCS[\"Astro_DOS_71_4_SHLG71\",GEOGCS[\"GCS_DOS_71_4\",DATUM[\"D_DOS_71_4\",SPHEROID[\"International_1924\",6378388.0,297.0]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]],PROJECTION[\"Transverse_Mercator\"],PARAMETER[\"False_Easting\",300000.0],PARAMETER[\"False_Northing\",2000000.0],PARAMETER[\"Central_Meridian\",-5.716666666666667],PARAMETER[\"Scale_Factor\",1.0],PARAMETER[\"Latitude_Of_Origin\",-15.96666666666667],UNIT[\"Meter\",1.0]]",
  "wkt2": "PROJCRS[\"Astro_DOS_71_4_SHLG71\",BASEGEOGCRS[\"GCS_DOS_71_4\",DATUM[\"D_DOS_71_4\",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\",300000.0],PARAMETER[\"False_Northing\",2000000.0],PARAMETER[\"Central_Meridian\",-5.716666666666667],PARAMETER[\"Scale_Factor\",1.0],PARAMETER[\"Latitude_Of_Origin\",-15.96666666666667]],CS[Cartesian,2],AXIS[\"Easting (X)\",east,ORDER[1]],AXIS[\"Northing (Y)\",north,ORDER[2]],LENGTHUNIT[\"Meter\",1.0],ID[\"EPSG\",\"7877\"]]",
  "description": "Astro DOS 71-4 SHLG71",
  "authority": "EPSG",
  "version": "9.0(10.6.0)",
  "deprecated": "no",
  "areaname": "St Helena - St Helena Island",
  "extent": {
    "slat": -16.08,
    "nlat": -15.85,
    "llon": -5.85,
    "rlon": -5.59
  }
}