Ever since the VRC Avatar State Behaviours were added to the Avatar SDK, it's been possible to import them into a World project. Although this feature is mostly unknown to most of the community, it still has its own use-cases. Some scenarios where you'd want the State Behaviours in a world project would be using parameter drivers to set avatar parameters based on conditions/states of games, or disabling tracking for certain parts of the model to prevent the animations being overridden by the locations of trackers or IK.

Since you currently have to pull over a specific DLL from the avatar SDK (VRCSDK3A), it makes it cumbersome to work with if any animators rely on the State Behaviours for the stations in the world, especially since we aren't allowed to redistribute the DLL ourselves.

If rewrites of the VRC stations are under consideration, it might be better to implement/expose some of these feature to Udon, like directly setting avatar parameters or applying animators without having to use stations.