It's the BUG mod, Better Unaltered Gameplay. As well as I understand it, it goes through all the information that could possibly be available to you if you take twenty or thirty minutes between each turn to look, and presents it in a way to access it much faster. As examples, It will tell you when a rival you have contact with founds a city. (Otherwise, you have to open dialogue with them every turn and look up their cities.) It will tell you if they are willing to trade resources. It will tell you if they are willing to sign peace or capitulate. It will tell you if your city is about to grow. It will tell you if your city is about to become unhappy or unhealthy, or if it already has. It will tell you if you can whip or rush something and how much it will cost. As you mentioned before, it tells you in a glance how many cities your opponents have and how much they like you. It's a great mod and once you figure out how to install it, you will never go back!