public Optional<BigInteger> getBlockRewardWei() {
    final Optional<String> configFileContent = JsonUtil.getString(forkConfigRoot, BLOCK_REWARD_KEY);

    if (configFileContent.isEmpty()) {
      return Optional.empty();
    }
    final String weiStr = configFileContent.get();
    if (weiStr.toLowerCase(Locale.ROOT).startsWith("0x")) {
      return Optional.of(new BigInteger(1, Bytes.fromHexStringLenient(weiStr).toArrayUnsafe()));
    }
    return Optional.of(new BigInteger(weiStr));
  }
Gets block reward wei.

@return the block reward wei
config/src/main/java/org/hyperledger/besu/config/BftFork.java