Um, I'm on the mailing list where this was announced and they are not
open source. So slurping up their stuff is not, so far as I know, OK.
-Original Message-
From: "Ralph Corderoy"
Sent: Thursday, March 30, 2017 6:31am
To: groff@gnu.org
Subject: [Groff] Unix Research Editions 8, 9, and 10 Available.
Hi,
Research Unix Editions 8, 9, and 10 will no longer have copyright
asserted over them.
https://www.spinellis.gr/cgi-bin/comment.pl?date=20170328 says they
contain, amongst other things, "graphics typesetting tools" so perhaps
there's something of interest to today's troff users in them.
Cheers, Ralph.