The 'locktime' value of a transaction usually specifies the earliest time that a transaction may be mined (included in a block). The value can take one of two forms: a block height (if the value is ≤ 500M), or a unix timestamp. The locktime value of this transaction seemingly indicates that the transaction cannot be mined until the year 2076. But, because this is a coinbase transaction (created by a miner in the process of mining a block), its locktime value does not need to honor the usual purpose, and may instead be representing some other data from the miner. This situation arises fairly regularly in coinbase transactions.