I have reviewed this document as part of the Operational directorate's ongoing effort to review all IETF documents being processed by the IESG.  These comments were written with the intent of improving the operational aspects of the IETF drafts. Comments that are not addressed in last call may be included in AD reviews during the IESG review.  Document editors and WG chairs should treat these comments just like any other last call comments.

In general, this document is clear to me. I did not see any special operational or network management related issue.

There are several clearification questions and nits as follows:

1. " The present document defines a number of control operators that did not make it into RFC 8610:" 
This confused me why it was not included into RFC 8610. Is there any WG decision to make this draft seperate from RFC8610?

2. Why this document is informational while RFC8610 is standard?
This somewhat related to the first question. 
I looked into the shepherd comments, but the reason is still not clear to me.

"This is Informational. It provides extensions to CDDL through an extension registry that's only "specification required". It is being done through the IETF process (and working group) because much of it was already planned to be shipped as "included batteries" with original CDDL, because there expertise on ABNF (which it is linking into CDDL) is in here, and because the proposed additions are expected to be used as important tools future CDDL-based specifications."

I do not think "an extension registry that's only "specification required"" should be the reason for informaitonal.

3. A nit in section 2: 
"As an 80 % solution" is not easy to understand what this mean to the later words.

Cheers,
Tianran