Essentially creating fake data that looks very realistic and creates narratives that would span real use cases. Some of this is simple (fake names with faker), some of it is a bit more manually guided (customer-specific terminology and specific business logic).

The goal here is for the data to both be useful for testing and provide coverage not just at a software level, but at a user story level. This helps test things like cross-application interactions; is also doubly helpful since we can use it for demos without screwing up production data.