I noticed SEUS downloaded 3 big files during upgrade, perhaps they contain MAIN, FS, and custom files??

The SEUS files have these names:
(30MB)
FILE_276672004_1236010537000_1235391054000_2766720 03_55175104_INFILE_LONGTERM
(24MB)
FILE_276669971_1236008983000_1235139783000_2766699 66_44492240_INFILE_LONGTERM
(6.7MB)
FILE_276608447_1232961761000_1232622518000_2764946 35_7005321_INFILE_LONGTERM

I can't resist to think they each contain MAIN, FS, or custom file. Can anyone confirm? If yes, has anyone any clue how to convert them into MAIN, FS, and custom files?

Cheers.