@HJB and @acpan, Thanks for engaging with my question.
At this point, it does seem easiest to just connect up some dummy database, so that my API calls can work. I thought that the simplest would be Excel or Access, but I have never gotten those to work on the internal webserver. The Access trial did work when I published it to the Demo Server. Anyway, I think I will create an empty MySQL database somewhere to serve as the "dummy".
The odd thing is that https://xlinesoft.com/phprunner/docs/rest-api-connections.htm seems to be the entry point to this subject, and doesn't mention that the API connections need to be able to write to a database, or that mirror tables need to be created for any REST views...that would seem to require a lot of maintenance.
So far, I have gotten football-data, a weather site, and one more API to return data, and the last two in my app published to the Demo Server.
I am going to do a test with a MySQL dummy database and report back.
I do think that whoever said that only the developer can answer this was correct - from the docs, I don't understand why it is required to connect to a database, but would like to, and have this addressed if it is not strictly necessary for some reason.
Again, thanks for the engagement.