For software that interfaces with Bitcoin Core via RPC, it can be useful to know whether the fRelayTxes flag is set. It could be added to `getnetworkinfo`.

pto->fSendMempool = false;
                CAmount filterrate = 0;
                {
                    LOCK(pto->cs_feeFilter);
                    filterrate = pto->minFeeFilter;
                }
                LOCK(pto->cs_filter);
                BOOST_FOREACH(const uint256& hash, vtxid) {
                    CInv inv(MSG_TX, hash);
                    pto->setInventoryTxToSend.erase(hash);
                    if (filterrate) {
                        CFeeRate feeRate;
                        mempool.lookupFeeRate(hash, feeRate);
                        if (feeRate.GetFeePerK() < filterrate)
                            continue;
                    }
                    if (pto->pfilter) {
                        CTransaction tx;
                        bool fInMemPool = mempool.lookup(hash, tx);
                        if (!fInMemPool) continue; 
                        if (!pto->pfilter->IsRelevantAndUpdate(tx)) continue;
                    }
                    pto->filterInventoryKnown.insert(hash);
                    vInv.push_back(inv);
                    if (vInv.size() == MAX_INV_SZ) {
                        pto->PushMessage(NetMsgType::INV, vInv);
                        vInv.clear();
                    }
                }
            }