I can't make heads or tails about it. When I open a grid project, including the templates, the default of the "Design For" application setting is "Support for Older Browsers" But, its clearly a grid design. Its not designing for an IE11 browser.

I haven't yet made my hands too dirty with the CSS grid, but I believe the default you mention is the fall-back for older browsers. IE11 doesn't understand 'display: grid', so the programme is making some magic (don't ask me exactly what) so that browsers like IE11 can display something decent.

Correct, but when I read the change log, and the web page about feature queries, there are screenshots of the an ie11 design (not from this app though). That would be an immense trial an error.

https://cssgrid.cc/examples/feature-queries-cssgrid.html
I am woefully misunderstanding how it works, or something got mixed up in the recent build post (its happened before, no biggie, but maybe CC does not know). So I want to ask here, because I know when I start posting in their support pages, eyes start to roll....

Alright, I think I am zeroing in on this now. In the application, in the upper left 'Design For" is the SAME as Styles:Apply Styles: Design For: Manage Support Queries.

I think the issue is, you can do grid design, on the fallback, and at this point, not exactly clear on what happens if you do that. But I believe when you get to the grid layout, or any styles that are grid-based, then you select the Design For in the Styles pane as Display Grid

Bob - where is that video?

Is this what you are looking for?
https://cssgrid.cc/video-tutorials/

Well, in there, I believe it was mentioned a 4th video about Feature Queries would be forthcoming.