Right now with a lot of presigned protocols (like lightning commitment transactions), you include a separate output thats small so that if you need to fee-bump the transaction you can CPFP that output. One problem with this is you need to have some funds locked up in this anchor. Another is that for something like lightning, each side needs to have an anchor. And also anchors are sort of unique and ad hoc. Instagibbs has been working on ephemeral anchors which are like a standardized 0-value anyone can spend output. So you dont have funds locked up, you only need one anchor and either party can bump it, and its composable with other protocols. The actual output is an OP_TRUE and then a little two byte tag. This release of bitcoin standardizes that output so nodes will relay those transactions. They’ve been consensus valid, but until now you would have had to hand them to a miner
