In this example, there is a total of $100m collateral for all KUSD tokens in the market. As KUSD price increases, the Collateral Ratio decreases. From the change in Collateral Ratio, there is now $250,000 of USDC which is now overcollateralized and is open for buyback to happen. When buyback happens, surplus USDC is withdrawn to the person who does the buyback, and provided DOPX of the same value will be burned from the system.