If you right click/edit on the mod you can see its name and a description of what it does as you see in game. For example "mod_HuntingRifle_Receiver_Heavier(OMOD)" is the Hardened Receiver for the hunting rifle. In the center of the edit window is where the item property modifiers are, you can see that the Hardened Receiver increases weight(fweight),attack damage(iattackdamage) and value(ivalue). Also "co_mod_HuntingRifle_Receiver_Heavier(COBJ)" is used to make the weapon mod show in the weapon crafting bench.