well i didnt look to deep into it yet but my first guess is to look for item_bonus.fos and if u want to know how magik lokcker functioning or other locker who spawns statted stuff just look at the .fos which handle it.
my guess for spawning statted items is that you have either to run some function or you could maybe , but i dont know , edit item values, vars w.e. with some scripted gm menu ... but thats just guessing except the item_bonus.fos which i looked up quick.
with some more investigation i think its quite easy to understand just requires some time being spent looking into it.