When a question is migrated from another site, a stub is temporarily left on the original site before being automatically deleted after 30 days. (See What is migration and how does it work?)
While questions stubs are automatically deleted from the origin site after 30 days, questions that are nearly a decade old will prominently display their migration status.
Migration notice for What is the cURL command-line syntax to do a POST request?
I can't think of any reason a 7-8 year old migration notice would be helpful for the average user, or why it should displayed before protected notices.