What does the sixth line in the output of the Bitcoin Core GUI RPC command "gettxoutsetinfo" mean? An example of the output of this RPC command is as follows.
 1  &quot;height&quot;:n,     (numeric) The current block height (index)
 2  &quot;bestblock&quot;: &quot;hex&quot;,   (string) The hash of the block at the tip of the chain
 3  &quot;transactions&quot;: n,      (numeric) The number of transactions with unspent outputs
 4  &quot;txouts&quot;: n,            (numeric) The number of unspent transaction outputs
 5  &quot;bogosize&quot;: n,          (numeric) A meaningless metric for UTXO set size
 6  &quot;hash_serialized_2&quot;: &quot;hash&quot;, (string) The serialized hash
 7  &quot;disk_size&quot;: n,         (numeric) The estimated size of the chainstate on disk
 8  &quot;total_amount&quot;: x.xxx          (numeric) The total amount
}

What's the meaning of the sixth line &quot;hash_serialized_2&quot;? Whose hash is this referring to?
It is a hash of the entire serialized UTXO set. You can use to verify that a node's UTXO set is uncorrupted (by comparing it with another node that runs the same command, at the same height).
The _2 prefix is to indicate the hashing algorithm that is used. Earlier versions used a different algorithm that became very hard to support efficiently. It's just there so people don't expect the hashes to be comparable between old and new nodes.