[Jack_Trowell]

Note : "manysites" is a dom3 terrain flag, same as "mountain" or "farm", you can see and change it when you use the official map editor ingame (or my own map editor). This flag increase the default chance of having a site in each slot of the province, and is often used in custom maps to give more value to a province without setting anything in stone.

For those that don't already know, each province has only 4 slots for sites, and each slot has on average 35-45% chance of having something (default settings depending on Era, plus small mod for some terrains types, such as farms having slightly less sites that default for exemple)

According to this, the "manysites" flag is supposed to increase those chances, probably doubling them of giving a fixed bonus like +25%, but even then you're never sure that all slots will be used.