Function bytecode_abi_fingerprint 

pub fn bytecode_abi_fingerprint() -> u32

Fingerprint of the bytecode ABI: every opcode (discriminant, name, operand widths, in enum order) and every builtin (index, name, in table order — OpGetBuiltin operands are indexes into that table). This is a compatibility sentinel, not integrity protection: safety against forged headers rests on the L1/L2/L3 checks, not on this value.