The way that these blockchain explorers identify the miner of a block is by looking at the arbitrary data which is included in the coinbase transaction of that block. Most mining pools tag blocks that they have mined by including their own name or a similar identifier in this data. For some reason, blockchain.com is not accurately extracting the Foundry tag from these blocks and displaying it on their website.
However, there will also be other miners that blockchain.com will be failing to properly identify, and there will be blocks which are not tagged by any miner at all, which will also be shown as "unknown".
The best thing to do would be to look up the block on a good explorer such as mempool.space (https://mempool.space/block/00000000000000000003362b9ce3fca0becc7657ed1221bc058f179fa6a94b99), and read the decoded data under the heading "Coinbase (Newly Generated Coins)" in the first transaction.