csak a kedvedért megnéztem egy FreeBSD 13.1-ről is, ugyan ez a helyzet
MAC-en és fBSD-n is
HISTORY
The whois command appeared in 4.3BSD.
Míg ubuntu-n:
HISTORY
This program closely tracks the user interface of the whois client developed at RIPE by Ambrose Magee and others on the base of the original BSD client.
AUTHOR
Whois and this man page were written by Marco d'Itri <md@linux.it> and are licensed under the terms of the GNU General Public License, version 2 or higher