This Datapack is an alternative to Mojang's decision not to add the goat horn in Minecraft 1.17 - 1.18.
So basically the datapack includes:

Goat Horn: Right click to sound the pillagers fearsome call to battle and gain buffs against the pillagers by giving them a glowing effect and revealing their location. You can get it by killing some goat, with a low drop chance.
One pillager from each raid or patrol can spawn with a goat horn in their left hand.