Default Tenant Database
From LongJump Support Wiki
When a new Tenant is created, the default database template is replicated and a new database is created for the new tenant.
If an ISV logs into this template database and modifies platform elements, the changes will be replicated when a new tenant is created, along with any changes to the database schema, workflows, policies, etc. Note that actual data is not replicated, only the platform elements/building blocks.