public Optional<BlockHeader> getOmmer(final int index) {
    return blockchain
        .getBlockHashByNumber(blockchain.getChainHeadBlockNumber())
        .flatMap(hash -> getOmmer(hash, index));
  }
Returns the ommer at the given index for the latest block.

@param index The index of the ommer in the blocks ommers list.
@return The ommer at the given index belonging to the latest block.
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/query/BlockchainQueries.java