MEDICINE_TECH, MILITARY_TECH, TRADE_TECH, DISCOVERY don't have an effect. The NATIVE_TECH one does as it tells the natives that this is a free tech for them. CONTACT_YIELD_GIFT_TECH this works with the Encomianda technology, the code checks to see if the player has this tech and if so you get more frequent Gifts from the indians. My net is still down or I'd explain the XML further. They are suppose to get it fixed in the morning.