Curiosities of coinbase transactions
The forgotten transaction
One of the most curious things about coinbase transactions is related to the first one. With the mining of the first genesis block in 2009, Satoshi Nakamoto generated a coinbase that was paid to the bitcoin address 1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa. Since then, at this address there are 50 BTC that cannot be spent. In fact, despite all the time and the number of blocks mined since then, that coinbase strangely remains unconfirmed.
There are many sources that assure that the reason for this fact remains undisclosed. However, there is another perspective. Transaction confirmations serve to represent how complicated it is to delete a transaction from a block. In this particular case, the first coinbase transaction has zero confirmations. And this transaction is encoded in the source code of the genesis block, on which the entire Bitcoin blockchain is built. The concept of confirmations would not apply because this transaction could not be eliminated. In case of doing so, a different chain would be being built, fact that would not make sense.
Another curious fact about coinbase transactions is that they can only be spent when reaching a certain level of confirmations, to be exact, 100 confirmations. This fact is known as Coinbase Madurity or Coinbase Transaction Maturity. This feature is embedded in Bitcoin's operating protocol, so it cannot be mocked in any way. That is, when the miners generate a block, the reward of that block and the commissions collected from it, will only really be available when the coinbase transaction reaches a total of 100 confirmations.
This rule was created in order to protect the blockchain in the event of a fork that could negatively affect transaction confirmation and coin generation. This is because it may be the case that during a confirmation orphan blocks are generated with a coinbase, but said block, coinbase and transactions within the block would be invalid for the new history of the blockchain after the hard fork. This prevents miners from taking advantage of generating coins by means of a coinbase in a forked blockchain with little computing power.