SLD99 3D - ESRI:104693

WKT

GEOGCS["SLD99_3D", 
	DATUM["D_Sri_Lanka_Datum_1999", 
		SPHEROID["Everest_Adjustment_1937", 6377276.345, 300.8017]], 
	PRIMEM["Greenwich", 0.0], 
	UNIT["Degree", 0.0174532925199433], 
	LINUNIT["Meter", 1.0]]

WKT2

GEOGCRS["SLD99_3D", 
	DATUM["D_Sri_Lanka_Datum_1999", 
		ELLIPSOID["Everest_Adjustment_1937", 6377276.345, 300.8017]], 
	PRIMEM["Greenwich", 0.0], 
	CS[ellipsoidal, 3], 
	AXIS["Longitude (lon)", east, 
		ORDER[1], 
		ANGLEUNIT["Degree", 0.0174532925199433]], 
	AXIS["Latitude (lat)", north, 
		ORDER[2], 
		ANGLEUNIT["Degree", 0.0174532925199433]], 
	AXIS["Ellipsoidal height (h)", up, 
		ORDER[3], 
		LENGTHUNIT["Meter", 1.0]], 
	ID["Esri", "104693"]]

Data from @esri/proj-codes

{
  "wkid": 104693,
  "latestWkid": 104693,
  "macro": "PE_GCS_SLD99_3D",
  "name": "SLD99_3D",
  "wkt": "GEOGCS[\"SLD99_3D\",DATUM[\"D_Sri_Lanka_Datum_1999\",SPHEROID[\"Everest_Adjustment_1937\",6377276.345,300.8017]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433],LINUNIT[\"Meter\",1.0]]",
  "wkt2": "GEOGCRS[\"SLD99_3D\",DATUM[\"D_Sri_Lanka_Datum_1999\",ELLIPSOID[\"Everest_Adjustment_1937\",6377276.345,300.8017]],PRIMEM[\"Greenwich\",0.0],CS[ellipsoidal,3],AXIS[\"Longitude (lon)\",east,ORDER[1],ANGLEUNIT[\"Degree\",0.0174532925199433]],AXIS[\"Latitude (lat)\",north,ORDER[2],ANGLEUNIT[\"Degree\",0.0174532925199433]],AXIS[\"Ellipsoidal height (h)\",up,ORDER[3],LENGTHUNIT[\"Meter\",1.0]],ID[\"Esri\",\"104693\"]]",
  "description": "SLD99 3D",
  "authority": "Esri",
  "version": "12.7.0",
  "deprecated": "no",
  "areaname": "Sri Lanka - onshore",
  "extent": {
    "slat": 5.86,
    "nlat": 9.88,
    "llon": 79.64,
    "rlon": 81.95
  }
}