With Core Data the file on disk is referenced as NSPersistentStore in Swift. The NSPersistentStrore class has a subclass called NSIncrementalStore, which is meant for subclassing. Whether you make calls to a file on disk or to a remote system using URLSession doesn't matter.
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When you're working with an NSManagedObjectContext and execute a query the implementation of that query is abstracted away. The only point where it matters where the call is going is in the code of the NSPersistentStore class or subclass.