On Sun, Dec 8, 2019 at 2:49 AM <arnold@skeeve.com> wrote:

> I'm pretty sure it was in 4.1.  It shipped as a binary only, IIRC.
>
That might be right.   At Tektronix, we had it one V7 on a PDP-11 in
the late 1970s (before we were running 4.1), and I know we had sources but
I have no memory of the provenance.   It was likely they came from a UCB
person working there in the summer (Mark Bales, Jim Kleckner or one of the
CAD folks would be the prime suspects).