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

Code before:
        base58Prefixes[SECRET_KEY] =     std::vector<unsigned char>(1,128);
        base58Prefixes[EXT_PUBLIC_KEY] = {0x04, 0x88, 0xB2, 0x1E};
        base58Prefixes[EXT_SECRET_KEY] = {0x04, 0x88, 0xAD, 0xE4};

        bech32_hrp = "bc";

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

        fDefaultConsistencyChecks = false;
        m_is_mockable_chain = false;

        m_assumeutxo_data = {
            {
                .height = 840'000,
                .hash_serialized = AssumeutxoHash{uint256{"a2a5521b1b5ab65f67818e5e8eccabb7171a517f9e2382208f77687310768f96"}},
                .m_chain_tx_count = 991032194,
                .blockhash = consteval_ctor(uint256{"0000000000000000000320283a032748cef8227873ff4872689bf23f1cda83a5"}),
            },
            {
                .height = 880'000,
                .hash_serialized = AssumeutxoHash{uint256{"dbd190983eaf433ef7c15f78a278ae42c00ef52e0fd2a54953782175fbadcea9"}},
                .m_chain_tx_count = 1145604538,
                .blockhash = consteval_ctor(uint256{"000000000000000000010b17283c3c400507969a9c2afd1dcf2082ec5cca2880"}),
            }
        };

        chainTxData = ChainTxData{
            // Data from RPC: getchaintxstats 4096 00000000000000000001b658dd1120e82e66d2790811f89ede9742ada3ed6d77
            .nTime    = 1741017141,
            .tx_count = 1161875261,
            .dTxRate  = 4.620728156243148,
        };
    }
};

/**
 * Testnet (v3): public test network which is reset from time to time.
 */
class CTestNetParams : public CChainParams {
public:
    CTestNetParams() {
        m_chain_type = ChainType::TESTNET;
        consensus.signet_blocks = false;
        consensus.signet_challenge.clear();
        consensus.nSubsidyHalvingInterval = 210000;
        consensus.script_flag_exceptions.emplace( // BIP16 exception
            uint256{"00000000dd30457c001f4095d208cc1296b0eed002427aa599874af7a432b105"}, SCRIPT_VERIFY_NONE);
        consensus.BIP34Height = 21111;
        consensus.BIP34Hash = uint256{"0000000023b3a96d3484e5abb3755c413e7d41500f8e2a5c3f0dd01299cd8ef8"};
        consensus.BIP65Height = 581885; // 00000000007f6655f22f98e72ed80d8b06dc761d5da09df0fa1dc4be4f861eb6
        consensus.BIP66Height = 330776; // 000000002104c8c45e99a8853285a3b592602a3ccde2b832481da85e9e4ba182

Review comment (suggestion):
2cc7d585600e8f0760f877fecf4e7eaf9c5dc92b: here's a torrent magnet, with the same seeds as Bitcoin Core v29, except the binary seed: `magnet:?xt=urn:btih:7019437a2b1530624b100c0795cfc5f90b8322ca&dn=utxo-910000.dat&tr=udp%3A%2F%2Ftracker.openbittorrent.com%3A80&tr=udp%3A%2F%2Ftracker.opentrackr.org%3A1337%2Fannounce&tr=udp%3A%2F%2Ftracker.coppersurfer.tk%3A6969%2Fannounce&tr=udp%3A%2F%2Ftracker.leechers-paradise.org%3A6969%2Fannounce&tr=udp%3A%2F%2Fexplodie.org%3A6969%2Fannounce&tr=udp%3A%2F%2Ftracker.torrent.eu.org%3A451%2Fannounce&tr=udp%3A%2F%2Ftracker.bitcoin.sprovoost.nl%3A6969`

It might be an hour or so before you can download it.

Reminder to other testers that loading the snapshot is _much_ faster if you disable the network temporary, see #29993.

Code after:
        base58Prefixes[SECRET_KEY] =     std::vector<unsigned char>(1,128);
        base58Prefixes[EXT_PUBLIC_KEY] = {0x04, 0x88, 0xB2, 0x1E};
        base58Prefixes[EXT_SECRET_KEY] = {0x04, 0x88, 0xAD, 0xE4};

        bech32_hrp = "bc";

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

        fDefaultConsistencyChecks = false;
        m_is_mockable_chain = false;

        m_assumeutxo_data = {
            {
                .height = 840'000,
                .hash_serialized = AssumeutxoHash{uint256{"a2a5521b1b5ab65f67818e5e8eccabb7171a517f9e2382208f77687310768f96"}},
                .m_chain_tx_count = 991032194,
                .blockhash = consteval_ctor(uint256{"0000000000000000000320283a032748cef8227873ff4872689bf23f1cda83a5"}),
            },
            {
                .height = 880'000,
                .hash_serialized = AssumeutxoHash{uint256{"dbd190983eaf433ef7c15f78a278ae42c00ef52e0fd2a54953782175fbadcea9"}},
                .m_chain_tx_count = 1145604538,
                .blockhash = consteval_ctor(uint256{"000000000000000000010b17283c3c400507969a9c2afd1dcf2082ec5cca2880"}),
            },
            {
                .height = 910'000,
                .hash_serialized = AssumeutxoHash{uint256{"4daf8a17b4902498c5787966a2b51c613acdab5df5db73f196fa59a4da2f1568"}},
                .m_chain_tx_count = 1226586151,
                .blockhash = consteval_ctor(uint256{"0000000000000000000108970acb9522ffd516eae17acddcb1bd16469194a821"}),
            }
        };

        chainTxData = ChainTxData{
            // Data from RPC: getchaintxstats 4096 00000000000000000000611fd22f2df7c8fbd0688745c3a6c3bb5109cc2a12cb
            .nTime    = 1756722903,
            .tx_count = 1235299397,
            .dTxRate  = 5.456290459519495,
        };
    }
};

/**
 * Testnet (v3): public test network which is reset from time to time.
 */
class CTestNetParams : public CChainParams {
public:
    CTestNetParams() {
        m_chain_type = ChainType::TESTNET;
        consensus.signet_blocks = false;
        consensus.signet_challenge.clear();
        consensus.nSubsidyHalvingInterval = 210000;