Anisotropy support was removed when VoxelGI was reworked as it was too demanding on the GPU.
* GIProbe is now VoxelGI * BakedLightmap is now LightmapGI As godot adds more ways to provide GI (as an example, SDFGI in 4.0), the different techniques (which have different pros/cons) need to be properly named to avoid confusion.