@RafaelCintron asked me a good question here that is underspecified. What happens if an app attempts to relate the "identity" reference space to any other space? I'd expect getPose to return null for that request, since a disconnected identity space is by definition not positioned with any stable relation to any real-world objects. However, we should probably specify that explicitly.

Originally posted by @thetuvix in https://github.com/immersive-web/webxr/pull/459/files