What is the purpose of a tub diverter and how does it function in a plumbing system?

The purpose of a tub diverter is to control the flow of water between the tub faucet and the showerhead in a Plumbing system. It functions by redirecting the water flow from the tub faucet to the showerhead when the diverter is activated, allowing the user to switch between filling the tub and using the shower.