The iPhone backup in iTunes is managed by a single file called Manifest.mbdb. The binary file contains information about all other files in the backup along with the file sizes and file system structure data.
Manifest.Mbdb file header and record format are shown below
Header: Mbdb file header is a fixed value of 6 bytes and the value acts as a magic number to identify the mbdb files.
Record: Mbdb file contain many records and each record is of variable size. Every record contains various details about a file.