The “plugin.dat” file located in the Data folder contains information on the object files registered for the game. It enables a check to be performed on the object files. It consists of a header followed by a sequence of “DAT file entries.”
00..03 : number of DAT files and a 'one' flag at bit 24
04..07 : total size of all DAT files
08..0B : date modified checksum
0C..0F : total size of all DAT file entries (this file size minus this header size)
10..13 : number of DAT files
Date modified checksum:
start with zero in a 4 byte checksum. Then the DAT files are stepped through and for each one, the low and high date modifed values are XOR'd together and then XOR'd with the checksum.