The " I " (ego/body) is just a concept like all others, except it (usually) accompanies all other concepts, i.e. when I observe an apple (and its environment) I also observe the ego/body, which appears to be doing the observing, but it isn't. Just like the apple it is being observed. (As The Zen master Hung Po said, "The observed cannot observe".)
Which basically means the
environment of the "apple" includes the ego-body.
I would say this "letting go" or "resting with" as JLNobody has phrased it, is to observe the apple (or any percept or thought) without observing the ego/body, absent the ego/body-self. Part of the difficulty is that most of us are locked into the impression that the ego-body-self is doing the observing.
I think this is in accord with the Cybernetics link fresco provided in the other thread though it probably goes a lot further, i.e. everything is landscape or environment
including the ego.
Any "effort" expended by the ego towards enlightenment or towards "letting go" or "resting with" (sorry JL,
) makes the ego grow in importance; as a percept in the landscape it gets bigger,
..by focusing attention on it, e.g. now the ego is going to rest or let go etc.
The paradoxical nature of our task is to observe without being an observer, without being a "somebody". Too simply(?) observe the ego for what it is; an object not a subject, which is the signal of death (imaginary) on one side of the coin and enlightenment on the other.