In this meditation, Sam Harris does an emptiness of self meditation. Daniel P Brown had identified this type of meditation as second stage in the stages of Mahamudra meditation. Here, I will put it into context of the 4/5 stages.
You look for the center and it drops away. And then there's experience of only the world or only consciousness, however you want to think about it.
This explanation describes the second step towards the experience of non-duality, as Daniel P Brown has identified it in the Heart Sutra: Going beyond Self.
Here, in short, are the "Going beyond" steps in sequence (look them up here for more detail):
Going beyond thought
Going beyond Self (the topic of today´s meditation)
Going beyond space and time
Going beyond localization and consciousness.
(Occasionally Dan Brown adds a 5th step: going beyong information process and particularization / partializing)
Sam Harris frequently touches all of these stages, without bringing them into a theoretical context. His meditations often contain a mixture of pointing out instructions pertaining to different stages.
Gebel, T. (2020d, July 16). The Heart Sutra as a complete spiritual development project. Till Gebel. https://www.till-gebel.com/post/heart-sutra-as-spiritual-development-project
Gebel, T. (2022u, October 2). Particularising - Sam Harris Daily Meditation 2022.08.24. Till Gebel. https://www.till-gebel.com/post/sam-harris-daily-meditation-2022-08-24-not-particularising