Years ago, I could manually seed the random number generator in FreeBSD by setting:
sysctl -w kern.random.sys.seeded=0
... and then if I deleted my SSH keys (on purpose) and restarted sshd, I would be forced to mash my keyboard for a page or two in order to seed the RNG. Then sshd would create new ssh keys based on that seed.
This is no longer possible - that sysctl no longer exists and sshd happily makes new keys every time I wipe the existing ones out.
I am not suggesting manually seeding the RNG is more secure - it's possible worse - but I am asking why it is no longer possible to do this, or, if it is, how I can do this in 2019 (FreeBSD 12).