[Maintainer] Help determining proper LICENSE for x11-wm/piewm?

A PR (https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=279111) has been
opened with the intent to supply a suitable LICENSE for the x11-wm/piewm
port.

I am the maintainer of the port (out of self-defense, more than anything
else); I am unable to determine what would make sense in this case:

* The most recent "copyright" notice I find is from 1991 (U. of
  Maryland).
* There also exist "copyright" notices from:
  * Don Hopkins (1989)
  * MIT (1989)
  * Solbourne Computer, Inc (1990)
  * Evans & Sutherland (1988)
  * HP & MIT (1989)
* As best I can determine, there are no explicit "license" statements in
  the distribution.

The creator of the PR suggested "MIT" for the license.  While I can't
claim that's wrong, I also can't claim it's right -- and my current
impression is that claiming something that is, in fact, not correct in
such a case is probably rather worse than making no claim at all.

I am no expert in law (in general) or Intellectual Property law (in
particular).  I would like to do "what's right."

Suggestions or advice?

Thanks.

Peace,
david.  I would like to do "what's right."

Suggestions or advice?

Thanks.

Peace,
david
-- 
David H. Wolfskill                              david@catwhisker.org
I will not be voting for a "unified reich" in the US.

See https://www.catwhisker.org/~david/publickey.gpg for my public key.