This file used to store eMule's configuration in it's earlier versions. Nowadays, it only stores the userhash and the configuration file version.
The current configuration file version is 20 (in hex: 0x14).
The file format is as follows:
Size of each field is as follows:
- Version: 1 byte
- Userhash: 16 bytes, stored as a big-endian 128-bit value.
The following is a hex dump of an hypothetic preferences.dat file:
14 2C 16 62 17 9C 0E CE 02 45 55 A8 5A 56 6C 6F 49
In the above example, the following data can be seen:
- Configuration file version: 20 (In hex: 0x14)
- Userhash: 2C1662179C0ECE024555A85A566C6F49