A DB3 file is a database file created by SQLite, a widely used, self-contained, serverless, and zero-configuration SQL database engine. It stores structured data in tables, rows, and columns, similar to other relational database management systems (RDBMS) like MySQL or PostgreSQL, but with a significantly smaller footprint and simpler architecture. DB3 files are commonly used in applications, embedded systems, and websites to store and manage data locally. They are highly portable and can be easily copied and moved between different systems. The SQLite database engine supports standard SQL queries, allowing developers to create, read, update, and delete data within the DB3 file. The file format is designed for efficiency and reliability, making it suitable for a wide range of applications where a lightweight database solution is required. DB3 files are often used for storing application settings, user data, and other persistent information.