SQLite is a self-contained, serverless, zero-configuration, transactional SQL database engine. It is the most widely deployed database engine in the world. The 'sqlite' file extension represents a database file created and managed by the SQLite database engine. These files store structured data in tables, similar to other relational database management systems (RDBMS). However, unlike client-server RDBMS like MySQL or PostgreSQL, SQLite databases are stored in a single file, making them highly portable and easy to embed within applications. SQLite is commonly used for local/client data storage in application software, embedded devices, and websites. It's a popular choice for applications that require a lightweight and easily manageable database solution without the overhead of a dedicated database server. The file contains the entire database schema, data, indexes, and other metadata necessary for the database to function. It is a binary file format.