On Mon, Jan 10, 2022 at 9:43 PM Larry McVoy <lm@mcvoy.com> wrote:
It's docs.  The *roff docs were locked up with the Unix license.

Larry point taken but ... I'm not so sure that specific statement is true.

It may have >>seemed<< that way to you, but I'm fairly sure that in fact, it was not.   The documents were published independently to the source and use of the binary license.  I do think that some had an AT&T copyright on them, but I'm not even sure all of them had a copyright associated.   The AT&T license in fact explicitly allowed replication of the documents that came with UNIX could be duplicated and distributed without violating the license.  Numerous people sold copies of them.  Any (student or not) could go into the MIT or Harvard Coop and buy a copy.   Same in the Berkeley area, IIRC Stacy's [a famous Telgraph ave bookstore] had the BSD (as well as other systems) manuals.

Beyond base duplication, numerous companies published parts of them and in particular parts if not all of the roff manual.  For instance, a firm in Seattle called CSSC published a number of reference guides and use guides based on them [I just found a number of copies of some of them this weekend as I'm resetting up my basement. I have a number of duplicates that I am offering to the hive BTW].

I do believe that you are correct that both the sources (and associated binaries) to original nroff/groff and ditroff were licensed and needed and an AT&T license, but not the documents themselves.