The Register has learned from those involved in the browser trade that Apple has limited the development and testing of third-party browser engines to devices physically located in the EU. That requirement adds an additional barrier to anyone planning to develop and support a browser with an alternative engine in the EU.
It effectively geofences the development team. Browser-makers whose dev teams are located in the US will only be able to work on simulators. While some testing can be done in a simulator, there’s no substitute for testing on device – which means developers will have to work within Apple’s prescribed geographical boundary.
… as Mozilla put it – to make it “as painful as possible for others to provide competitive alternatives to Safari.”
I assume they are doing checks of other things. Local software is not the same as a web service that is checking your IP for your location.
They could use location services, your registration country for your Apple ID, the sale location of your device, and other things. They could even aggregate indicators and use that.
iOS would have root access to aGPS (or even real GPS) to determine location. There’s no easy way to spoof that against a determined asshole actor.