Does Bubble have its own database?

Does Bubble, the popular no-code platform, maintain its own dedicated database system? I'm curious to know if this platform, which allows users to create web applications without traditional coding, relies on an internal, proprietary database structure. Would this database be specifically designed to handle the unique needs of Bubble's applications, ensuring scalability, performance, and data security? Or does Bubble utilize an external database service or integrate with existing database solutions? Understanding this aspect of Bubble's architecture would greatly assist in evaluating its suitability for various projects and use cases.