default Block getGenesisBlock() {
    final Hash genesisHash =
        getBlockHashByNumber(BlockHeader.GENESIS_BLOCK_NUMBER)
            .orElseThrow(() -> new IllegalStateException("Missing genesis block."));
    return getBlockByHash(genesisHash)
        .orElseThrow(() -> new IllegalStateException("Missing genesis block."));
  }
Returns the header for the current chain head.

@return the header for the current chain head
ethereum/core/src/main/java/org/hyperledger/besu/ethereum/chain/Blockchain.java