Function unshield_extra_sighash_data_v0 

pub fn unshield_extra_sighash_data_v0(
    output_address: &[u8],
    unshielding_amount: u64,
) -> Vec<u8> 

v0 byte layout of unshield_extra_sighash_data (see that function’s doc comment for the layout and rationale). Frozen: never mutate; a layout change requires a new _v1 + version bump.