Call of Pripyat: Redux is the premiere realism/difficulty modification for the latest game in the S.T.A.L.K.E.R. series. Version 1.0 (released) brings numerous enhancements and tweaks to the game while retaining its original charm, but making the Zone a much more difficult place to survive. Version 2.0 (in development) will build upon the success of v1.0 and bring a huge range of improvements over its predecessor, including new missions, NPCs, script systems and even levels.
In v2.0, we'll be introducing 'Redux Caches'. When searching dead NPCs, you have a chance to discover the location of one of these caches (a system I'm sure you're familiar with). Which caches are found is dependant on the level you're on, the rank of the NPC you kill, their faction, and a random element. Caches will contain interesting, useful or rare loot and will often tell a small story/be part of something larger. You can find caches on your own without knowing their location beforehand. Exploration is important!