To add onto pdknsk's answer, App Engine project names that have the "s~" prefix mean that you selected to have your application hosted <https://cloud.google.com/appengine/docs/locations> in America during project creation time.
Alternatively you could also see the "e~" prefix if you selected Europe as your App Engine project region. It is best practice to use the App Engine project name without the prefix. -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To unsubscribe from this group and stop receiving emails from it, send an email to google-appengine+unsubscr...@googlegroups.com. To post to this group, send email to google-appengine@googlegroups.com. Visit this group at https://groups.google.com/group/google-appengine. To view this discussion on the web visit https://groups.google.com/d/msgid/google-appengine/38fe8ab2-807f-4a9c-8f44-bea44fb1407b%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.