[Bacardi]

I looked yesterday between CS:S, CS:GO and L4D2 vpk files signatures.

Seem Orange Box games (cs:s, tf2, dod:s) has this signature system (I'm like 99% sure),
but CS:GO and L4D2 do not have signature in they vpk files.
I assume, these two games not have same system. Maybe hidden feature ? Dunno.