I hate myself a little bit, but I posted an answer to the 'BSD license
origin' in this twitter thread
https://twitter.com/bsdimp/status/1572521676268802049
that people might find interesting.
Please note the caveats at the end of the thread: This is a bare outline
hitting the high points taking only data from release files with no behind
the scenes confirmation about why things changed, nor in-depth exploration
of variations that I know are present, nor do I got into examples from
various USENET postings from the time that stole the license for people's
own different uses.
Nonetheless, I hope it's useful...
Warner