The extension is a little weakly defined

[LPardue]

This is an editorial matter and subjective. The actual extension gubbins are fine, I just find that the references to the concept of the extenstion is pretty weak.

For instance, the introduction is literally 1 sentence and says just "This document describes a QUIC extension for an endpoint to control its peer's delaying of acknowledgements.". It would be nicer to expand this a little bit to let the reader in on what type of extension we're talking about - for example, datagrams mentions there are frame types https://datatracker.ietf.org/doc/html/rfc9221#section-1 but I suspect that this draft has a little more nuance.