Using Global in quotations here for ease of understanding. Global will be in context of the running service in Staging or Production.
Anything stored in the repository will be global and anything stored in the database will be per environment. Vault can be either per environment or global. For custom messaging, I recommend either Wedge_address_configs or UI_Text(https://docs.q2developer.com/docs/guides/online_integration/ui_text.html)
-Trey