Are you referring to MARA’s slip stream? You pay them thousands of dollars for them to use their hash rate to only include your large data set/ transaction, enough to fill an entire block if you want. It’s using their nodes block template to be selective of certain “transactions” and then using the full force of their hash rate to mine that block with their set filters. There’s actually no guarantee that the block will be mined believe it or not. It’s also the exact equivalent to what I’m trying to explain. I have a a spam filter, they take money to filter everything but spam. The same but very different. I also only have 5 TH backing my template haha. But if I were to mine a block, there wouldn’t be any more than 83kb of data per transaction for my block. So all in all, my argument is that Core decided to remove my ability to filter what transactions my node sees. That’s why I switched to Knots.