flavors
http://www.midnightbsd.org/

2020
Samoilov - FreeBSD ru
    https://www.youtube.com/watch?v=4VaJeB_bf6E
    ! BSD - is not just a kernel, but a full OS
    ! no systemd, no udisks2 (bskisks is still raw)
2018
LazzyLaif - About FreeBSD ru of 25:45
    https://www.youtube.com/watch?v=6AoqSB4dPx8
    ! illegal lexics: no single kernel
2017
GoldenPlay - Unix History - BSD Unix
    https://www.youtube.com/watch?v=CMfveo_I0YI
    ! modular kernel (no need to rebuild kernel while adding new drivers)
    ! OpenBSD is a brilliant and most secured: OpenSSH, OpenSSL, LibreSSL, tmux, 
    ! DragonflyBSD: threads isolation ???