You can read it there: https://github.com/btc1/bitcoin/commit/c11c37b0d6cf434b6565b2d70ed5aa2b1e63ba3e

src/chainparams.cpp
+        // Deployment of SegWit2x
+        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT2X].bit = 4;
+        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT2X].nStartTime = 1496275200; // June 1st, 2017.
+        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT2X].nTimeout = 1510704000; // November 15th, 2017.

src/consensus/consensus.h
+/** BIP102 block size increase height */
+static const unsigned int BIP102_FORK_MIN_HEIGHT = 485218;
+static const unsigned int BIP102_FORK_BUFFER = (144 * 90);