0x2f2ff15d?0x2f2ff15d is the function selector for grantRole(bytes32,address). Grants a privileged role.
When a transaction's data begins with 0x2f2ff15d, it is calling grantRole. The selector is the first four bytes of the keccak-256 hash of the signature grantRole(bytes32,address), which is how wallets and explorers work out which function a payload is for.