My own experience in a Daniel P Brown retreat.  I have described it here: the room in which I was suddenly darkened - dark-purple "stripe" overlaid the visual field, and then there was a perception of "awareness differentiating itself and then looking back at itself".  

I found a near identical description in Metzinger´s "The Elephant and the Blind"

"I perceived subject and object as the same substance, facing each other like the two inner surfaces of a folded sheet of paper. As if subject and object were created by folding the fundamental substance and the observer were placed arbitrarily on one of the two sides. [\#2916]"

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This chapter explores "Pure Awareness," a non-conceptual state of mind experienced in deep meditation as profound silence and stillness. This experience transcends the ordinary subject-object duality, shifting from a state of an "observer" watching mental content to awareness becoming aware of itself. This reflexive process is described metaphorically as awareness "dynamically folding back into itself," resulting in a non-dual, nonegoic form of self-knowing. Although this state is silent and beyond thought, it possesses a distinct quality of self-certainty and clarity. Ultimately, this reveals a fundamental "zero-person perspective" where the experience of knowing is not owned by a self but arises as a natural, unconstructed state of the organism.