Repository: bitcoin/bitcoin
File: src/kernel/chainparams.cpp (C++)

Code before:
        consensus.fPowNoRetargeting = false;
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit = 28;
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = Consensus::BIP9Deployment::NEVER_ACTIVE;
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].min_activation_height = 0; // No activation delay
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].threshold = 1512; // 75%
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].period = 2016;

        // Deployment of Taproot (BIPs 340-342)
        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].bit = 2;
        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nStartTime = 1619222400; // April 24th, 2021
        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nTimeout = 1628640000; // August 11th, 2021
        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].min_activation_height = 0; // No activation delay
        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].threshold = 1512; // 75%
        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].period = 2016;

        consensus.nMinimumChainWork = uint256{"0000000000000000000000000000000000000000000015f5e0c9f13455b0eb17"};
        consensus.defaultAssumeValid = uint256{"00000000000003fc7967410ba2d0a8a8d50daedc318d43e8baf1a9782c236a57"}; // 3974606

        pchMessageStart[0] = 0x0b;
        pchMessageStart[1] = 0x11;
        pchMessageStart[2] = 0x09;
        pchMessageStart[3] = 0x07;
        nDefaultPort = 18333;
        nPruneAfterHeight = 1000;
        m_assumed_blockchain_size = 200;
        m_assumed_chain_state_size = 19;

        genesis = CreateGenesisBlock(1296688602, 414098458, 0x1d00ffff, 1, 50 * COIN);
        consensus.hashGenesisBlock = genesis.GetHash();
        assert(consensus.hashGenesisBlock == uint256{"000000000933ea01ad0ee984209779baaec3ced90fa3f408719526f8d77f4943"});
        assert(genesis.hashMerkleRoot == uint256{"4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"});

        vFixedSeeds.clear();
        vSeeds.clear();
        // nodes with support for servicebits filtering should be at the top
        vSeeds.emplace_back("testnet-seed.bitcoin.jonasschnelli.ch.");
        vSeeds.emplace_back("seed.tbtc.petertodd.net.");
        vSeeds.emplace_back("seed.testnet.bitcoin.sprovoost.nl.");
        vSeeds.emplace_back("testnet-seed.bluematt.me."); // Just a static list of stable node(s), only supports x9
        vSeeds.emplace_back("seed.testnet.achownodes.xyz."); // Ava Chow, only supports x1, x5, x9, x49, x809, x849, xd, x400, x404, x408, x448, xc08, xc48, x40c

        base58Prefixes[PUBKEY_ADDRESS] = std::vector<unsigned char>(1,111);
        base58Prefixes[SCRIPT_ADDRESS] = std::vector<unsigned char>(1,196);
        base58Prefixes[SECRET_KEY] =     std::vector<unsigned char>(1,239);
        base58Prefixes[EXT_PUBLIC_KEY] = {0x04, 0x35, 0x87, 0xCF};
        base58Prefixes[EXT_SECRET_KEY] = {0x04, 0x35, 0x83, 0x94};

        bech32_hrp = "tb";

        vFixedSeeds = std::vector<uint8_t>(std::begin(chainparams_seed_test), std::end(chainparams_seed_test));

Review comment (suggestion):
Seems low, would expect 244.

```
$ du -csh --apparent-size testnet3/chainstate/ testnet3/blocks/
16G	testnet3/chainstate/
205G	testnet3/blocks/
221G	total
```

Code after:
        consensus.MinBIP9WarningHeight = 836640; // segwit activation height + miner confirmation window
        consensus.powLimit = uint256{"00000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffff"};
        consensus.nPowTargetTimespan = 14 * 24 * 60 * 60; // two weeks
        consensus.nPowTargetSpacing = 10 * 60;
        consensus.fPowAllowMinDifficultyBlocks = true;
        consensus.enforce_BIP94 = false;
        consensus.fPowNoRetargeting = false;
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit = 28;
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = Consensus::BIP9Deployment::NEVER_ACTIVE;
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].min_activation_height = 0; // No activation delay
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].threshold = 1512; // 75%
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].period = 2016;

        // Deployment of Taproot (BIPs 340-342)
        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].bit = 2;
        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nStartTime = 1619222400; // April 24th, 2021
        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nTimeout = 1628640000; // August 11th, 2021
        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].min_activation_height = 0; // No activation delay
        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].threshold = 1512; // 75%
        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].period = 2016;

        consensus.nMinimumChainWork = uint256{"0000000000000000000000000000000000000000000016dd270dd94fac1d7632"};
        consensus.defaultAssumeValid = uint256{"0000000000000065c6c38258e201971a3fdfcc2ceee0dd6e85a6c022d45dee34"}; // 4550000

        pchMessageStart[0] = 0x0b;
        pchMessageStart[1] = 0x11;
        pchMessageStart[2] = 0x09;
        pchMessageStart[3] = 0x07;
        nDefaultPort = 18333;
        nPruneAfterHeight = 1000;
        m_assumed_blockchain_size = 240;
        m_assumed_chain_state_size = 19;

        genesis = CreateGenesisBlock(1296688602, 414098458, 0x1d00ffff, 1, 50 * COIN);
        consensus.hashGenesisBlock = genesis.GetHash();
        assert(consensus.hashGenesisBlock == uint256{"000000000933ea01ad0ee984209779baaec3ced90fa3f408719526f8d77f4943"});
        assert(genesis.hashMerkleRoot == uint256{"4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"});

        vFixedSeeds.clear();
        vSeeds.clear();
        // nodes with support for servicebits filtering should be at the top
        vSeeds.emplace_back("testnet-seed.bitcoin.jonasschnelli.ch.");
        vSeeds.emplace_back("seed.tbtc.petertodd.net.");
        vSeeds.emplace_back("seed.testnet.bitcoin.sprovoost.nl.");
        vSeeds.emplace_back("testnet-seed.bluematt.me."); // Just a static list of stable node(s), only supports x9
        vSeeds.emplace_back("seed.testnet.achownodes.xyz."); // Ava Chow, only supports x1, x5, x9, x49, x809, x849, xd, x400, x404, x408, x448, xc08, xc48, x40c

        base58Prefixes[PUBKEY_ADDRESS] = std::vector<unsigned char>(1,111);
        base58Prefixes[SCRIPT_ADDRESS] = std::vector<unsigned char>(1,196);
        base58Prefixes[SECRET_KEY] =     std::vector<unsigned char>(1,239);