Unrest Supplies are used to build Contention at a Foreign port. They are an alternative to sinking foreign ships, particularly for Freetraders who don't want to ruin their Reputation with the Foreign Trade Unions.
Unrest Supplies can cover almost everything produced: Wood, Food, Metal, Luxuries, Textiles. Additionally, some things are requested specifically: Rum, Small Arms, Gold.
The worth of these has yet to be decided upon. The amount of Unrest they produce has been increased, although some say that the cost of producing the supplies far outweighs the reward they give.