bitcoin/doc/release-notes-26646.md

JSON-RPC

The testmempoolaccept RPC now returns 2 additional results within the "fees" result: "effective-feerate" is the feerate including fees and sizes of transactions validated together if package validation was used, and also includes any modified fees from prioritisetransaction. The "effective-includes" result lists the wtxids of transactions whose modified fees and sizes were used in the effective-feerate (#26646).