Blob assets have explicit ownership so they need to be manually disposed when no longer needed. The only exception to this is if they are created during scene conversion and serialized into a scene, then the blob asset is owned by the scene and will be deallocated when the scene is unloaded. For now there are no plans for making it possible to query if a blob asset needs disposing. The reason for not exposing this is that we might end up optimizing away the header of the blob assets when packing them into one block in a subscene. Documentation will be updated to clarify when created colliders need to be disposed.