Good comment, Viktorija. Both mindfulness and Vipassana meditations are hard to put in a single category, and how an individual meditates in their own practice can sway this categorization even more. For instance, one Vipassana practitioner might really focus on the breath and notice some sensations throughout (which would lean towards FA), while another might focus on the breath but subdue that focus until it is almost equal to the focus they place on their surroundings (more like OM). It’s likely that the benefits these meditators gain are divided between the FA benefits and OM benefits, dependent on how their practice looks.

That said, the scientific community tends to place Vipassana meditations into the OM group (see here and here). Mindfulness meditation is sometimes put into the FA group and sometimes put into the OM group (and sometimes just defined as the same as Vipassana). I believe this difference is because of the variations in mindfulness. As you put it, mindfulness meditations are made to be digestible, and so a lot of practitioners spend a lot of time in the FA phase of just focusing on their breath. I struggled with where to put mindfulness for the sake of this paper, but found enough papers that studied just the FA part of mindfulness that I followed suit there and noted that mindfulness meditation often flows into an OM phase. Thanks for commenting and giving me space to clarify that!