M-Files Storage

Hello,

When we create an object in M-Files or data that is not saved in the database, where and with what system is it saved? Does it have a database that we cannot see, running in its own background? What is the hierarchy of classes and class groups where they are recorded? Does it have a database system where ids are defined as primary keys and kept as a corresponding object or data? I would be happy if anyone with knowledge on the subject could help.

Thanks in advance for your answers.