Dinning Table slot name

I'm trying to make a dining table, I need to modify some values, But I don't understand what some slots do. I need help.
I guessed part of it ↓
(1)b__subroot(?)
(2)_ctnm_chr (chair position)
(3)_ctnm_eat (place to put bowls or plates)
(4)_ctnm_drink (drink position)
(5)_ctnm_sitIndividual(?)
(6)_ctnm_sitShared(?)
(7)_ctnm_placemat(placemat position)