Average Terrestrial System 1977 - EPSG:4122

WKT

GEOGCS["GCS_ATS_1977", 
	DATUM["D_ATS_1977", 
		SPHEROID["ATS_1977", 6378135.0, 298.257]], 
	PRIMEM["Greenwich", 0.0], 
	UNIT["Degree", 0.0174532925199433]]

WKT2

GEOGCRS["GCS_ATS_1977", 
	DATUM["D_ATS_1977", 
		ELLIPSOID["ATS_1977", 6378135.0, 298.257]], 
	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", "4122"]]

Data from @esri/proj-codes

{
  "wkid": 4122,
  "latestWkid": 4122,
  "macro": "PE_GCS_ATS_1977",
  "name": "GCS_ATS_1977",
  "wkt": "GEOGCS[\"GCS_ATS_1977\",DATUM[\"D_ATS_1977\",SPHEROID[\"ATS_1977\",6378135.0,298.257]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]]",
  "wkt2": "GEOGCRS[\"GCS_ATS_1977\",DATUM[\"D_ATS_1977\",ELLIPSOID[\"ATS_1977\",6378135.0,298.257]],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\",\"4122\"]]",
  "description": "Average Terrestrial System 1977",
  "authority": "EPSG",
  "version": "6.5(4.0.0)",
  "deprecated": "no",
  "areaname": "Canada - Maritime Provinces",
  "extent": {
    "slat": 43.41,
    "nlat": 48.07,
    "llon": -69.05,
    "rlon": -59.73
  }
}