Which version of WGS 84 apply

Hello, do you know which version of WGS 84 is used in Cesium? (WGS 84 (G730), WGS 84 (G873), WGS 84 (G1150), or WGS 84 (G1674))

I think it is one of those two:

This question was also answered on Github different projections · Issue #3877 · CesiumGS/cesium · GitHub