New params of chainparams.cpp. What put on them and how generate?

Question

What do these parameters do and what to insert there

        uint256S("00000fffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"); //what this do ? end what put to here

        consensus.nRuleChangeActivationThreshold = 6048; // 75% of 8064 //what this do end what put ?
        consensus.nMinerConfirmationWindow = 8064; // nPowTargetTimespan / nPowTargetSpacing * 4  //what this do ?
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit = 28; //what this setting's do ? 
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = 1199145601; // January 1, 2008
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = 1230767999; // December 31, 2008

        // Deployment of BIP68, BIP112, and BIP113.
        consensus.vDeployments[Consensus::DEPLOYMENT_CSV].bit = 0;
        consensus.vDeployments[Consensus::DEPLOYMENT_CSV].nStartTime = 1485561600; // January 28, 2017
        consensus.vDeployments[Consensus::DEPLOYMENT_CSV].nTimeout = 1517356801; // January 31st, 2018

        // Deployment of SegWit (BIP141, BIP143, and BIP147)
        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].bit = 1;
        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].nStartTime = 1485561600; // January 28, 2017
        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].nTimeout = 1517356801; // January 31st, 2018

        // The best chain should have at least this much work.
        consensus.nMinimumChainWork = uint256S("0x000000000000000000000000000000000000000000000006805c7318ce2736c0"); //what this do end what put here ?

        // By default assume that the signatures in ancestors of this block are valid.
        consensus.defaultAssumeValid = uint256S("0x1673fa904a93848eca83d5ca82c7af974511a7e640e22edc2976420744f2e56a"); //1155631  //what this do ?

        nPruneAfterHeight = 100000;  //what this do ?

i need to reconfigure exist coin to new wallet but stuck on this param's.

For all who down vote question, i try find about this param info , but do not find anything, or you simple down vote what you do not understand ?

I understand it's start end time out time. But how it work's.

Answer 1

uint256S("00000fffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"); //what this do ? end what put to here

The first line describes a minimum difficulty.

consensus.nRuleChangeActivationThreshold = 6048; // 75% of 8064 //what this do end what put ?
consensus.nMinerConfirmationWindow = 8064; // nPowTargetTimespan / nPowTargetSpacing * 4  //what this do ?

The next two lines say that rule changes require 75% agreement, measured across 4 retargeting periods.

consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit = 28; //what this setting's do ? 
consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = 1199145601; // January 1, 2008
consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = 1230767999; // December 31, 2008

// Deployment of BIP68, BIP112, and BIP113.
consensus.vDeployments[Consensus::DEPLOYMENT_CSV].bit = 0;
consensus.vDeployments[Consensus::DEPLOYMENT_CSV].nStartTime = 1485561600; // January 28, 2017
consensus.vDeployments[Consensus::DEPLOYMENT_CSV].nTimeout = 1517356801; // January 31st, 2018

// Deployment of SegWit (BIP141, BIP143, and BIP147)
consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].bit = 1;
consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].nStartTime = 1485561600; // January 28, 2017
consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].nTimeout = 1517356801; // January 31st, 2018

The next eleven lines describe the minimum and maximum times that three softforks can activate, and how they are to be signaled using version bits.

// The best chain should have at least this much work.
consensus.nMinimumChainWork = uint256S("0x000000000000000000000000000000000000000000000006805c7318ce2736c0"); //what this do end what put here ?

The next two lines specify the minimum amount of chain work that a client must have before it will consider itself synchronized.

// By default assume that the signatures in ancestors of this block are valid.
consensus.defaultAssumeValid = uint256S("0x1673fa904a93848eca83d5ca82c7af974511a7e640e22edc2976420744f2e56a"); //1155631  //what this do ?

The next two lines disables signature checks on blocks that are ancestors of the block specified by that block hash.

nPruneAfterHeight = 100000;  //what this do ?

The next two lines disable block pruning on blocks below a certain height. In Bitcoin, this is because most of the initial blocks are empty. This is documented in this commit.