Aha! Generating worlds from seeds, now
that is right out of my Apple-IIe playbook!

I had been thinking look at those depots, how do all those vehicles get there? Those industrial-vehicle suppliers are
smooth operators! Maybe those are a deus ex machina just begging for a "UFOs and black helicoptors" explanation, maybe the depots are a good place to start; maybe I can make an industrial-vehicles pak that keeps track of total sales and the mysterious "who-ever it is that is
out there" can vie with one-another picking which modes of locomotion to buy into the importing of; maybe even which brands of which modes.
Then at the end of the game - or a possibly a periodic accounting in the case of endless games - they can compare their sales-figures and settle any side-wagers they might sportingly have made among themselves.
I had fired up OpenTTD again by that point, so had just used their look at online content button and grabbed a bunch of plugins for them, setting AIs against one-another; so went to go get pak128 for Simutrans and discovered oops there does not seem to be a built-in update-and-upgrade in my (Ubuntu 18.04 LTS) Simutrans client. I found it anyway, somewhere where the pak descriptions were largely not in English, but it got an error trying to load. I found what seemed to be the same list, in English, but it seemed to link to the same version on Sourceforge. So I am presently momentatily derailed by the attempt to get a working pack to start attempting small modifications of to dip my toes into the water so to speak.
However just reading up on how to make a pak led me to think it does not seem itself to provide scripting, so I had arrived back at the idea of looking into that Squirrel thing that unfortunately would by the sound of it only work on non-Extended Simutrans for now. But hey, non-Extended is what Ubuntu sees fit to provide, so maybe I can just go ahead on that angle for now and worry about getting it to work under Extended later when if nothing else I'd be more familiar with what it was that needed to be gotten working...
So thanks for that, from seeds I can create billions of entire galaxies full of worlds if I choose to do so!

Though truth to tell I had to break up the 36-character string co-ordinates I was using (and still use actually to set co-ordinates for the FreeCiv worlds in the
Galactic Milieu) into smaller pieces for the IIe's 6-byte reals to digest them piece by piece into distance calculations, and needed to make a tiny simple assembly-language "use a sequence of 36 arbitrary bytes as seed" random-number generator.
I am off to go look at that Squirrel thing again...

Though I did discover that there is or had been a pak with an automobiles industries chain so would be interested in finding out where, if anywhere, one gets hold of paks that work with Ubuntu's off-the-shelf Simutrans 120.2.2
-MarkM-