How does a miner identify himself There has been a new mining pool appearing after the halving called Lubian.com cf https://www.cryptoglobe.com/latest/2020/05/new-bitcoin-mining-pool-comes-out-of-nowhere-already-5th-largest/

How does a miners say to the world who he is, and how can he prove he is the one that has mined a specific block ?
They will either reuse the address in coinbase transaction subsidy output every time they mine a block, and then publicly claim that address, or they will "tag" their name (ascii-encoded) and some metadata in an OPRETURN or the scriptSig of the coinbase transaction. 

Here's the coinbase TX from block 603526:

https://blockstream.info/tx/0eb39c3f1a6813dfe5bb9d86dd71de2593aa76f25d4f25b149c9f564eb33cd54

The script sig is

03863509fabe6d6d0f3e894118566fd52beccf2a405c060fb701171dd16d83f1fb4aa0219fa8656601000000000000002469020000535e15a74a1b00000000e6892f736c7573682f

which is ASCII for:

5  z&gt;mm&gt;   AVoU+lO*@\7Qmq{J !(ef$iS^'J /slush/

There's slushpool!