Ok so, when #FreeBSD switched #ZFS to #OpenZFS in 13.0, a lot of sysctl knobs got new names, and the old ones retained as aliases. I now want to get rid of them, but I don't know how deep they go in code, tools, documentation and oral histories.

Since I'm here for code cleanup and not to ruin anyone's day, I could use an assist from old FreeBSD+ZFS boffins. Please review https://github.com/openzfs/zfs/pull/17375 and let me know if there are any that would be bad to remove, and why. Thank you!