So, this is just complete speculation, but I was playing the Korea scenario recently and I noticed that not only does the scenario-only civ of Manchuria have a unique icon, but they also have a map:
In addition to this, their unique unit (Banner cavalry) have a unique flag, although I believe their model is the Keshik. Finally, the atlas from the DLC has two placeholder icons, presumably for Manchuria since they're the only other units in the DLC.
Then of course we have the Wonders of the Ancient World, with both Sumer and the Hittites being entirely new civs, with the exception only of leaderheads. They're the most complete scenario civs ever, with all the art present.
Denmark and Polynesia are less clear, although it's possible that Denmark was originally going to be in a pack with Norway since we have the Ski Infantry and Norway is present in the scenario. Polynesia on the other hand is the only one I can't figure out. The only thing I could think of would be something like Hawaii and the Maori, but then the Moai miss out and neither are in the scenario.
In addition to this, their unique unit (Banner cavalry) have a unique flag, although I believe their model is the Keshik. Finally, the atlas from the DLC has two placeholder icons, presumably for Manchuria since they're the only other units in the DLC.
Then of course we have the Wonders of the Ancient World, with both Sumer and the Hittites being entirely new civs, with the exception only of leaderheads. They're the most complete scenario civs ever, with all the art present.
Denmark and Polynesia are less clear, although it's possible that Denmark was originally going to be in a pack with Norway since we have the Ski Infantry and Norway is present in the scenario. Polynesia on the other hand is the only one I can't figure out. The only thing I could think of would be something like Hawaii and the Maori, but then the Moai miss out and neither are in the scenario.