Already found many useful information regarding the chainstats db.
such as: What are the keys used in the blockchain levelDB (ie what are the key:value pairs)?
But what is the meanning of the last item?
'B' -> 32-byte block hash: the block hash up to which the database represents the unspent transaction outputs.
Is that means there is a row in the db, which key is a constant 'B' and value is the latest block hash?
