I'm a programmer, so I am perfectly aware of how to implement a behaviour tree. I don't want to rely on third party tools, but still have convenient tools for creating the AI for my game.
I was looking at tools like this one but I could not find out how to create editor extensions like that in Unity.
I also noticed that there is a new experimental feature (Playables) in the current versions of Unity.
Does this use the state machine editor from the Animator? Should/Could I use that to implement a behaviour tree?