These abilities help characters to hide things and find things respectively. Additional levels in the Hide ability provide bonuses to the 3d6 hide check used to hide things, including hiding oneself or hiding objects in a room.
Find Hidden similarly provides bonuses by level, but rather than using a special check, it piggy-backs on perception checks. Things are easier to find when the player is making an effort to find them.
These are minor abilities, common in backstories. They can also be learned by theives, assassins, and rogues or cross-class.
Worth a minor ability to get a little bonus on stealth when you have a chance to hide? Would you stack Find Hidden to help track down secret doors and other goodies? Let us know in the comments below.