There was a question raised in freebsd-questions@ mail list[1] about the "who"
parameters in this man page. It followed with some criticism about the choice of
words and the arcane language.
It seems OpenBSD[2] amd NetBSD[3] both have more legible descriptions so I
borrowed some of their ideas to try and make this page clearer.
[1] https://lists.freebsd.org/pipermail/freebsd-questions/2020-October/291914.html
[2] https://man.bsd.lv/renice
[3] https://man.netbsd.org/renice.8