I built https://stratum.work to get this block template stuff in front of more eyes. It shows real time template data sent to miners to work on and you can watch for similarities between pools yourself.
This thread does a great job explaining the data:
nostr:note1qckcs4y67eyaawad96j7mxevucgygsfwxg42cvlrs22mxptrg05qtv0jz3
When all merkle branches for a pool match another pool (colored cells), it means that they are using the same block template.
You can also see custom transaction prioritization, like a tx accelerator, when there’s a lower than normal fee rate for the “first transaction”.
