Op Cat and covenants

Op Cat is a powerful opcode that allows users to concatenate and split data in Bitcoin script. It enables the creation of covenants, which are controls over where coins can be moved. One example is the use of vaults, where coins are required to sit in a staging area before being moved to their final destination. This provides additional security against theft. Another example is in the efficient withdrawal of coins from exchanges, where users can choose when and at what fee rate to claim their coins. While Op Cat is a small and simple addition, it is seen as an important step towards enabling covenants in Bitcoin and improving the flexibility and control users have over their funds.