After building any of the blacksmith’s upgrades in a province, the description says that doing so provides a “weapon +X”.

What does this mean? Does it add up X points to the melee attack of any unit built in that province?

If so, for instance, if I train a let’s say a Halberdier in a province with the maximum blacksmith upgrade (weapon +3) that means that would mean that such unit will be as effective as a Chivalric Foot Knight but with more men?

Thanks for the heads up.