Okay, did some digging and found some gltf files in install directory:
extensions": {
"ENS_material": {
"specular": 0.0,
"imageFade": 1.0,
"indexOfRefraction": 1.0,
"billboardType": 0,
"materialType": 0,
"isSolidGlass": false,
"bumpMapType": 0,
"albedoColor": [
0.6000000238418579,
0.6000000238418579,
0.6000000238418579,
1.0
],
"tintColor": [
1.0,
1.0,
1.0,
1.0
],
"waterParams": {
"waterColor": [
1.0,
1.0,
1.0,
1.0
],
"windDirection": [
1.0,
0.0
],
"waveHeight": 0.10000000149011612,
"waveScale": 1.0,
"causticsIntensity": 1.0