Umbriel 2000 - ESRI:104959

WKT

GEOGCS["GCS_Umbriel_2000", 
	DATUM["D_Umbriel_2000", 
		SPHEROID["Umbriel_2000_IAU_IAG", 584700.0, 0.0]], 
	PRIMEM["Reference_Meridian", 0.0], 
	UNIT["Degree", 0.0174532925199433]]

WKT2

GEOGCRS["GCS_Umbriel_2000", 
	DATUM["D_Umbriel_2000", 
		ELLIPSOID["Umbriel_2000_IAU_IAG", 584700.0, 0.0]], 
	PRIMEM["Reference_Meridian", 0.0], 
	CS[ellipsoidal, 2], 
	AXIS["Longitude (lon)", east, 
		ORDER[1]], 
	AXIS["Latitude (lat)", north, 
		ORDER[2]], 
	ANGLEUNIT["Degree", 0.0174532925199433], 
	ID["Esri", "104959"]]

Data from @esri/proj-codes

{
  "wkid": 104959,
  "latestWkid": 104959,
  "macro": "PE_GCS_XT_UMBRIEL_2000",
  "name": "GCS_Umbriel_2000",
  "wkt": "GEOGCS[\"GCS_Umbriel_2000\",DATUM[\"D_Umbriel_2000\",SPHEROID[\"Umbriel_2000_IAU_IAG\",584700.0,0.0]],PRIMEM[\"Reference_Meridian\",0.0],UNIT[\"Degree\",0.0174532925199433]]",
  "wkt2": "GEOGCRS[\"GCS_Umbriel_2000\",DATUM[\"D_Umbriel_2000\",ELLIPSOID[\"Umbriel_2000_IAU_IAG\",584700.0,0.0]],PRIMEM[\"Reference_Meridian\",0.0],CS[ellipsoidal,2],AXIS[\"Longitude (lon)\",east,ORDER[1]],AXIS[\"Latitude (lat)\",north,ORDER[2]],ANGLEUNIT[\"Degree\",0.0174532925199433],ID[\"Esri\",\"104959\"]]",
  "description": "Umbriel 2000",
  "authority": "Esri",
  "version": "9.0.0",
  "deprecated": "no",
  "areaname": "Body",
  "extent": {
    "slat": -90,
    "nlat": 90,
    "llon": -180,
    "rlon": 180
  }
}