There is a pop message. A single one that pops up if anything was built in your capital, and it includes ALL infrastructure built. It also indicates that your palace got stronger. It appears only once and is easy to ignore/overlook, but it’s there. I was taking a test-drive with the new Khmer civ, and I had Persia, Timurids, and Inuit on my continent with me. Persia proceeded to wipe the floor with both the Inuit and the Timurids simultaneously. Timur has no bonuses prior to medieval unless he is winning wars, and Inuit’s star had them pinned on a tundra against a much stronger Persian starting position, so no real surprises, necessarily, but it was a pretty rapid and dramatic beat down. It makes me suspect that my custom civs are on the weak side in general.