I note that there is no grub file in '/etc/default/'
there is a grub file in '/usr/share/grub/default/' and the timeout there is set to =0
making a copy of this grub into '/etc/default/' has no effect
regardless, on boot, there is a GNU GRUB that starts after 4 seconds...
(a) how/where do I set its' timeout to 0 and more importantly,
(b) how/where do I disable the many lines of boot-up text?

The Boot Splash and Splash screen options of Workspace/Startup and Shutdown don't help...
i.e. the None Splash doesn't do none and
the Breeze Boot Splash doesn't do the logo...

I had one computer where /etc/default/grub disappered in an update. Result: all those lines you are talking about.
I copied the fle from another computer to this one. After that I did run 'update-grub' to update
# /boot/grub/grub.cfg, I think that is necessary. It worked in my case.

Did you run update-grub after putting a copy of grub in /etc/default/ ?

gerdeg wrote:Did you run update-grub after putting a copy of grub in /etc/default/ ?

Yes...
I've done this before but thank you for asking nonetheless
the point really was that this action had no affect on that pesky GNU grub
that wasn't there before a previous update...