Explorer Mode: Make it clear what colonies are included

Explorer mode has a visually simple coutry list, which makes it really simple to select counties but does not show all landmasses that count as in that country.

Their are still many colonies today, some of them acrost the ocean from their mother country. It is not clear which ones count and which ones do not. My understanding is that Puerto Rico does not count as america, but I know from a recent playthrough that islands off of Africa's west coast count as Spain.

Geopolitics are complicated, and even Google maps is not certain which landmasses belong to which country. Explorer mode would benefit from a clear list or map of all possible locations where you miget be put.