Constant runtime_common::constants::POLKADOT_BONDING_DURATION_IN_BLOCKS

pub const POLKADOT_BONDING_DURATION_IN_BLOCKS: BlockNumber = 28 * 6 * POLKADOT_EPOCH_DURATION_IN_SLOTS; // 0x0006_2700u32

28 eras for unbonding (28 days). Six sessions in an era (24 hours)