Does it know about my body?

Only if you open that part yourself. How you sleep, what tires you, what hurts — it is some of the most recognisable matter a person has, and it sits next to health, so nothing of it is kept until you say yes on the What you are made of page. Closing it stops the gathering at once, everywhere, and erasing what was already kept is a separate choice. Selione never asks for a diagnosis, a treatment or a measurement, and gives no medical advice.