title: NSManagedObjectModel versionIdentifiers
body: <p>The documentation for NSManagedObjectModel -versionIdentifiers says,</p>
  
  <blockquote>
    <p>The Core Data framework does not give models a default identifier, nor does it depend this value at runtime. For models created in Xcode, you set this value in the model inspector.</p>
  </blockquote>
  
  <p>I am not sure, but I think that setting version identifiers might help me as I go about coding model migration policy classes. Does anyone know how one might set these identifiers in Xcode? I have poked around a fair bit without success.</p>
  
  <p>Thanks.</p>