Thank you for your feedback. I will try to clarify to comments on the observation builder to make it more understandable.
The distance is calculated from the current agents position. Thus, it tells the agent how far away the observed target of the other agent is from the current location of the observing agent.
The current node is the one being constructed in the tree observation. It is the next branching point along the agents path. I will update the comment soon and also implement an example on how to use it.
Also I will make the baselines Repo publicly available so you can see how to use the observation in a training setup.