Monte Mario (Rome) - EPSG:4806

WKT

GEOGCS["GCS_Monte_Mario_Rome", 
	DATUM["D_Monte_Mario", 
		SPHEROID["International_1924", 6378388.0, 297.0]], 
	PRIMEM["Rome", 12.45233333333333], 
	UNIT["Degree", 0.0174532925199433]]

WKT2

GEOGCRS["GCS_Monte_Mario_Rome", 
	DATUM["D_Monte_Mario", 
		ELLIPSOID["International_1924", 6378388.0, 297.0]], 
	PRIMEM["Rome", 12.45233333333333, 
		ANGLEUNIT["Degree", 0.0174532925199433]], 
	CS[ellipsoidal, 2], 
	AXIS["Latitude (lat)", north, 
		ORDER[1]], 
	AXIS["Longitude (lon)", east, 
		ORDER[2]], 
	ANGLEUNIT["Degree", 0.0174532925199433], 
	ID["EPSG", "4806"]]

Data from @esri/proj-codes

{
  "wkid": 4806,
  "latestWkid": 4806,
  "macro": "PE_GCS_MONTE_MARIO_ROME",
  "name": "GCS_Monte_Mario_Rome",
  "wkt": "GEOGCS[\"GCS_Monte_Mario_Rome\",DATUM[\"D_Monte_Mario\",SPHEROID[\"International_1924\",6378388.0,297.0]],PRIMEM[\"Rome\",12.45233333333333],UNIT[\"Degree\",0.0174532925199433]]",
  "wkt2": "GEOGCRS[\"GCS_Monte_Mario_Rome\",DATUM[\"D_Monte_Mario\",ELLIPSOID[\"International_1924\",6378388.0,297.0]],PRIMEM[\"Rome\",12.45233333333333,ANGLEUNIT[\"Degree\",0.0174532925199433]],CS[ellipsoidal,2],AXIS[\"Latitude (lat)\",north,ORDER[1]],AXIS[\"Longitude (lon)\",east,ORDER[2]],ANGLEUNIT[\"Degree\",0.0174532925199433],ID[\"EPSG\",\"4806\"]]",
  "description": "Monte Mario (Rome)",
  "authority": "EPSG",
  "version": "4.5(3.0.1)",
  "deprecated": "no",
  "areaname": "Italy - including San Marino and Vatican",
  "extent": {
    "slat": 34.76,
    "nlat": 47.1,
    "llon": 5.93,
    "rlon": 18.99
  }
}