In Xcode 12, there is a new checkbox "Optimized for Mac UI" which can be checked. This is not possible so far. And because of that, the device idiom is always "ipad". But even if the checkbox would be checked in the generated Xcode project, it would never be "mac", because Titanium only checks for iPads and fallbacks to iPhones if not matching. This can be extended easily in the PlatformModule.m.