It adds compatibilit betwen tinkers construct and better combat
more exact it makes the weapons from tinker construct work with better combat animation
for it to work you need off course
tinker : https://www.curseforge.com/minecraft/mc-mods/tinkers-construct
bettercombat : https://www.curseforge.com/minecraft/mc-mods/better-combat-by-daedelus
works with the addons like
https://www.curseforge.com/minecraft/mc-mods/tinkers-things-json
https://www.curseforge.com/minecraft/mc-mods/tinkers-reforged