0xf2fde38b?0xf2fde38b is the function selector for transferOwnership(address). Hands control of the contract to a different address.
When a transaction's data begins with 0xf2fde38b, it is calling transferOwnership. The selector is the first four bytes of the keccak-256 hash of the signature transferOwnership(address), which is how wallets and explorers work out which function a payload is for.