private File generateTraceFile(
      final Path traceDir,
      final Hash blockHash,
      final int indexTransaction,
      final Transaction transaction) {
    return traceDir
        .resolve(
            String.format(
                "block_%.10s-%d-%.10s-%s",
                blockHash.toHexString(),
                indexTransaction,
                transaction.getHash().toHexString(),
                System.currentTimeMillis()))
        .toFile();
  }
Used to produce debug traces of transactions
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/processor/TransactionTracer.java