Constant zebra_chain::transaction::unmined::MEMPOOL_TRANSACTION_LOW_FEE_PENALTY

const MEMPOOL_TRANSACTION_LOW_FEE_PENALTY: u64 = 40_000;

When a transaction pays a fee less than the conventional fee, this low fee penalty is added to its cost for mempool eviction.

See VerifiedUnminedTx::eviction_weight() for details.