File with a .MWB extension contains an EER model of a relational database – its project which defines charts, display and procedures, and also permissions and other elements of a database. Such files are used to save projects of databases and to generate on their basis a real database.

MWB files are used by the MySQL Workbench software, which provides a graphic interface used to create and manage MySQL databases. This program, after a MWB project is finished, can generate a database, on the basis of it.