When I first started reading the Luna series, I thought they were Augmented Reality avatars of a person's AI assistant (think of them, in practical terms, like a really smart Siri). Apparently, each person "skins" them with a particular look and sticks to it and the books fairly often talks about what they look iike.
But reading the 3rd book, I see that sometimes people reference the looks of another person's familiar. Are they then like externally-visible holograms instead of just AR-to-the-owner? Are they AR avatars that are broadcast to persons nearby?