EssentialPIM uses an open-source Firebird database engine. You can access database directly using any Firebird database management tool. A good example of such a tool is Interbase Query. Here's the info you're going to need to open the database:
- Login: SYSDBA
- Password: masterkey
- SQL dialect: 3
Please note, you should have at least some understanding about how to work with the database files, otherwise data loss may occur.