I will try,
This consciousness that does not establish and grow, is an awarennes that only slightly contacts what is being experienced. Slightly, because it does not grow on what it experiences. It knows what arises but does not get involved in it because it does not grow on it. It is a simple and pure awareness and nothing more.
For example pain; it knows pain, pain is felt, but there is no involvement at all in the pain because it does not grow and really become established on the pain. Therefor the phyiscal pain is no burden for the mind. There is attention, there is contact, but no involvement because involvement means this vinnana must grow. That does not happen.
So i would say it is a kind of vinnana that is only aware and nothing more, pure awareness.