Voirol 1875 (grads) - ESRI:104139

WKT

GEOGCS["GCS_Voirol_1875_Grad", 
	DATUM["D_Voirol_1875", 
		SPHEROID["Clarke_1880_IGN", 6378249.2, 293.4660212936265]], 
	PRIMEM["Greenwich", 0.0], 
	UNIT["Grad", 0.01570796326794897]]

WKT2

GEOGCRS["GCS_Voirol_1875_Grad", 
	DATUM["D_Voirol_1875", 
		ELLIPSOID["Clarke_1880_IGN", 6378249.2, 293.4660212936265]], 
	PRIMEM["Greenwich", 0.0], 
	CS[ellipsoidal, 2], 
	AXIS["Longitude (lon)", east, 
		ORDER[1]], 
	AXIS["Latitude (lat)", north, 
		ORDER[2]], 
	ANGLEUNIT["Grad", 0.01570796326794897], 
	ID["Esri", "104139"]]

Data from @esri/proj-codes

{
  "wkid": 104139,
  "latestWkid": 104139,
  "macro": "PE_GCS_VOIROL_1875_GRAD",
  "name": "GCS_Voirol_1875_Grad",
  "wkt": "GEOGCS[\"GCS_Voirol_1875_Grad\",DATUM[\"D_Voirol_1875\",SPHEROID[\"Clarke_1880_IGN\",6378249.2,293.4660212936265]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Grad\",0.01570796326794897]]",
  "wkt2": "GEOGCRS[\"GCS_Voirol_1875_Grad\",DATUM[\"D_Voirol_1875\",ELLIPSOID[\"Clarke_1880_IGN\",6378249.2,293.4660212936265]],PRIMEM[\"Greenwich\",0.0],CS[ellipsoidal,2],AXIS[\"Longitude (lon)\",east,ORDER[1]],AXIS[\"Latitude (lat)\",north,ORDER[2]],ANGLEUNIT[\"Grad\",0.01570796326794897],ID[\"Esri\",\"104139\"]]",
  "description": "Voirol 1875 (grads)",
  "authority": "Esri",
  "version": "10.0.0",
  "deprecated": "no",
  "areaname": "Algeria - north of 32~N",
  "extent": {
    "slat": 31.99,
    "nlat": 37.14,
    "llon": -2.95,
    "rlon": 9.09
  }
}