Adds caravans belonging to many of the various factions in the world. They generally only spawn in the areas around their homes or outposts, so don't expect to find a Hiver Caravan up on the Leviathan Coast for example. They also tend to behave as you might expect of their parent faction, so a Holy Caravan will not be too fond of other races.
It's always best to import after installing or uninstalling a mod. Make sure you do it. Enjoy! :)