[TUHS] Documenter's Workbench versions

[Kevin Bowling]

I am reading some UNIX text processing books and am interested in the
lineage of Documenter's Workbench.

I see documentation of 1.0 (i.e
https://archive.org/details/sysv-dwb/page/n5/mode/2up)
I see a copy of 2.0 for 3B2 (i.e.
https://archives.loomcom.com/3b2/software/Documenters_Workbench/)

>From there things get a little less clear, it seems like we jump to
3.2 with SysVR3.2?

Then there is a 3.3 version https://github.com/n-t-roff/DWB3.3

One of my books from the late 80s references 3.4 available as a source
code purchase independent of UNIX.

Then it appears SGI might have had a 4.x strain?  (i.e.
https://archive.org/details/sgi_Documenters_Workbench_4.1.3)

Heirloom is derived from OpenSolaris which is derived from?

Can anyone firm this lineage up a bit; and is 4.x an SGI thing or what
(I extracted the image, the relnotes inside might as well not exist).

Regards,
Kevin