Interesting transactions from F2Pool

Lately, I've noticed that each block mined by F2Pool includes a unique transaction. The input address is 1JRhv7zRN9xCyTntYT5nuupg7JMsE7YocL. The output has an OP_RETURN that seems to be meaningless, along with two tiny BTC outputs going to specific addresses or maybe a black hole. Then there’s a change address. The craziest part? This transaction has zero fees, meaning it was added by the pool itself. I’m really curious about what these transactions are for. Anyone got any ideas?

The fees for those transactions are not zero as can be seen on a block explorer, but they are low. The OP_RETURN feature means those transactions are unspendable. It was added to the network to reduce the incidence of people including messages into a transaction and increasing the size of it, that can be done now using the OP_RETURN command.

It appears that they are also working on "Stacks Blockchain" while mining Bitcoin blocks. For example: This zero-fee "special transaction" of theirs: blockstream.info/tx/1e6d26895507a570b99d2333f90e139f607064bf9c96ef78703de9e5d3683cd2 Which is included to Bitcoin block #838098 is used as "Anchor transaction ID" of this Stacks (STX) block #145,526

Excellent. I know the practical use of these transactions. Thank you very much!