Clarke 1866 - EPSG:4008

WKT

GEOGCS["GCS_Clarke_1866", 
	DATUM["D_Clarke_1866", 
		SPHEROID["Clarke_1866", 6378206.4, 294.9786982]], 
	PRIMEM["Greenwich", 0.0], 
	UNIT["Degree", 0.0174532925199433]]

WKT2

GEOGCRS["GCS_Clarke_1866", 
	DATUM["D_Clarke_1866", 
		ELLIPSOID["Clarke_1866", 6378206.4, 294.9786982]], 
	PRIMEM["Greenwich", 0.0], 
	CS[ellipsoidal, 2], 
	AXIS["Latitude (lat)", north, 
		ORDER[1]], 
	AXIS["Longitude (lon)", east, 
		ORDER[2]], 
	ANGLEUNIT["Degree", 0.0174532925199433], 
	ID["EPSG", "4008"]]

Data from @esri/proj-codes

{
  "wkid": 4008,
  "latestWkid": 4008,
  "macro": "PE_GCS_CLARKE_1866",
  "name": "GCS_Clarke_1866",
  "wkt": "GEOGCS[\"GCS_Clarke_1866\",DATUM[\"D_Clarke_1866\",SPHEROID[\"Clarke_1866\",6378206.4,294.9786982]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]]",
  "wkt2": "GEOGCRS[\"GCS_Clarke_1866\",DATUM[\"D_Clarke_1866\",ELLIPSOID[\"Clarke_1866\",6378206.4,294.9786982]],PRIMEM[\"Greenwich\",0.0],CS[ellipsoidal,2],AXIS[\"Latitude (lat)\",north,ORDER[1]],AXIS[\"Longitude (lon)\",east,ORDER[2]],ANGLEUNIT[\"Degree\",0.0174532925199433],ID[\"EPSG\",\"4008\"]]",
  "description": "Clarke 1866",
  "authority": "EPSG",
  "version": "3.0(3.0.1)",
  "deprecated": "no",
  "areaname": "Not specified",
  "extent": {
    "slat": -90,
    "nlat": 90,
    "llon": -180,
    "rlon": 180
  }
}