The "Horizon" OS used on the Nintendo Switch is not FreeBSD-based, it merely contains some FreeBSD code, but is largely, as far as I am aware, a home-grown prop

The "Horizon" OS used on the Nintendo Switch is not FreeBSD-based, it merely contains some FreeBSD code, but is largely, as far as I am aware, a home-grown proprietary operating system not substantially based on any "free" system. The Sony PlayStation 4 (and probably PlayStation 5) actually are substantially based on FreeBSD, though.