For example, GTA: SA pal layout:

F,\default.xbe,4018176,347390

What means F,? and what means 347390?

I know that 4018176 is filesize.

If i modified some files in DATA folder, what I should change in lyt file?
filesize, what else?

I installed new script file (main.scm). All works perfectly but when i try to get in the car/bike, it's reading error.
i think lyt modifing can help.