Eckert IV (world) - ESRI:54012

WKT

PROJCS["World_Eckert_IV", 
	GEOGCS["GCS_WGS_1984", 
		DATUM["D_WGS_1984", 
			SPHEROID["WGS_1984", 6378137.0, 298.257223563]], 
		PRIMEM["Greenwich", 0.0], 
		UNIT["Degree", 0.0174532925199433]], 
	PROJECTION["Eckert_IV"], 
	PARAMETER["False_Easting", 0.0], 
	PARAMETER["False_Northing", 0.0], 
	PARAMETER["Central_Meridian", 0.0], 
	UNIT["Meter", 1.0]]

WKT2

PROJCRS["World_Eckert_IV", 
	BASEGEOGCRS["GCS_WGS_1984", 
		DYNAMIC[
			FRAMEEPOCH[1990.5], 
			MODEL["AM0-2"]], 
		DATUM["D_WGS_1984", 
			ELLIPSOID["WGS_1984", 6378137.0, 298.257223563]], 
		PRIMEM["Greenwich", 0.0], 
		CS[ellipsoidal, 2], 
		AXIS["Latitude (lat)", north, 
			ORDER[1]], 
		AXIS["Longitude (lon)", east, 
			ORDER[2]], 
		ANGLEUNIT["Degree", 0.0174532925199433]], 
	CONVERSION["Eckert_IV", 
		METHOD["Eckert_IV"], 
		PARAMETER["False_Easting", 0.0], 
		PARAMETER["False_Northing", 0.0], 
		PARAMETER["Central_Meridian", 0.0]], 
	CS[Cartesian, 2], 
	AXIS["Easting (X)", east, 
		ORDER[1]], 
	AXIS["Northing (Y)", north, 
		ORDER[2]], 
	LENGTHUNIT["Meter", 1.0], 
	ID["Esri", "54012"]]

Data from @esri/proj-codes

{
  "wkid": 54012,
  "latestWkid": 54012,
  "gcsWkid": 4326,
  "macro": "PE_PCS_WORLD_ECKERT_IV",
  "name": "World_Eckert_IV",
  "wkt": "PROJCS[\"World_Eckert_IV\",GEOGCS[\"GCS_WGS_1984\",DATUM[\"D_WGS_1984\",SPHEROID[\"WGS_1984\",6378137.0,298.257223563]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]],PROJECTION[\"Eckert_IV\"],PARAMETER[\"False_Easting\",0.0],PARAMETER[\"False_Northing\",0.0],PARAMETER[\"Central_Meridian\",0.0],UNIT[\"Meter\",1.0]]",
  "wkt2": "PROJCRS[\"World_Eckert_IV\",BASEGEOGCRS[\"GCS_WGS_1984\",DYNAMIC[FRAMEEPOCH[1990.5],MODEL[\"AM0-2\"]],DATUM[\"D_WGS_1984\",ELLIPSOID[\"WGS_1984\",6378137.0,298.257223563]],PRIMEM[\"Greenwich\",0.0],CS[ellipsoidal,2],AXIS[\"Latitude (lat)\",north,ORDER[1]],AXIS[\"Longitude (lon)\",east,ORDER[2]],ANGLEUNIT[\"Degree\",0.0174532925199433]],CONVERSION[\"Eckert_IV\",METHOD[\"Eckert_IV\"],PARAMETER[\"False_Easting\",0.0],PARAMETER[\"False_Northing\",0.0],PARAMETER[\"Central_Meridian\",0.0]],CS[Cartesian,2],AXIS[\"Easting (X)\",east,ORDER[1]],AXIS[\"Northing (Y)\",north,ORDER[2]],LENGTHUNIT[\"Meter\",1.0],ID[\"Esri\",\"54012\"]]",
  "description": "Eckert IV (world)",
  "authority": "Esri",
  "version": "3.0.1",
  "deprecated": "no",
  "areaname": "World",
  "extent": {
    "slat": -90,
    "nlat": 90,
    "llon": -180,
    "rlon": 180
  }
}