Agadez - EPSG:4206

WKT

GEOGCS["GCS_Agadez", 
	DATUM["D_Agadez", 
		SPHEROID["Clarke_1880_IGN", 6378249.2, 293.4660212936265]], 
	PRIMEM["Greenwich", 0.0], 
	UNIT["Degree", 0.0174532925199433]]

WKT2

GEOGCRS["GCS_Agadez", 
	DATUM["D_Agadez", 
		ELLIPSOID["Clarke_1880_IGN", 6378249.2, 293.4660212936265]], 
	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", "4206"]]

Data from @esri/proj-codes

{
  "wkid": 4206,
  "latestWkid": 4206,
  "macro": "PE_GCS_AGADEZ",
  "name": "GCS_Agadez",
  "wkt": "GEOGCS[\"GCS_Agadez\",DATUM[\"D_Agadez\",SPHEROID[\"Clarke_1880_IGN\",6378249.2,293.4660212936265]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]]",
  "wkt2": "GEOGCRS[\"GCS_Agadez\",DATUM[\"D_Agadez\",ELLIPSOID[\"Clarke_1880_IGN\",6378249.2,293.4660212936265]],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\",\"4206\"]]",
  "description": "Agadez",
  "authority": "EPSG",
  "version": "6.5(3.0.1)",
  "deprecated": "no",
  "areaname": "Niger",
  "extent": {
    "slat": 11.69,
    "nlat": 23.53,
    "llon": 0.16,
    "rlon": 16
  }
}