In June 2018, at the DotFmp, Fabrice Nordmann had launched a small challenge. How to Get the native date format of the system in which FileMaker runs (without plugin). The discussion had lasted some time and a few beers. Unfortunately (too drunk I went back to my hotel) I missed the solution found by David Julot. As I have not found his solution, I had to find one. The trick I found is to use "Insert Calculated Result" The file was created on a French Canadian Mac system (yyyy-mm-dd). Please test it and tell me if it’s working on a system other than US or French (I have tested those configuration).
And if you need it use-it... free as in beer