The user of-course can already implicitly work out this information from comparing the fee-rate with the actual fee.

I think that it would be useful for people not wanting to do this arithmetic in their head.

{
private:
    
    const uint256 hash;
public:
    
    static const int32_t CURRENT_VERSION=1;
    
    
    
    
    static const int32_t MAX_STANDARD_VERSION=2;
    
    
    
    
    
    const int32_t nVersion;
    const std::vector<CTxIn> vin;
    const std::vector<CTxOut> vout;
    CTxWitness wit; 
    const uint32_t nLockTime;
    
    CTransaction();
    
    CTransaction(const CMutableTransaction &tx);
    CTransaction& operator=(const CTransaction& tx);
    ADD_SERIALIZE_METHODS;
    template <typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {