Outlook Express Database (DBX)
Outlook Express uses the Outlook Express Database (DBX) database to store emails, folders, etc.
DBX files of Outlook Express 5.0 (OE5) and later start with hexadecimal: 0xcf 0xad 0x12 0xfe. For now it is assumed that this is the file signature.
According to libdbx OE4 uses a different signature: 4A4D4636 03001000. For now this is unconfirmed.
In OE the DBX files are used to store email per top folder (e.g. Inbox, Outbox) and the folder-hierarchy.