I am the assigned ART-ART reviewer for this draft. 

Summary: 
I think this document is concise and generally good, but a few things are not explained well enough. Please consider revising the following points.

Minor issues:
- It is unclear how to provide "alternative ASCII addresses" in Section 5.3.2 and how to distinguish between an EAI address and an alternative ASCII address, so it would be better to add an explanation.

- It is unclear how to verify the code points of domain names in Section 8, so it would be better to add an explanation.
RFC5892 describes how to determine the code points that can be used in IDNA2008 but does not describe how to validate domain name code points. So it would be easier to convey the intention to the reader to write "validate whether the domain name consists of the code points allowed by IDNA2008" rather than just writing "validate all code points in the domain name according to IDNA2008". 
Also, if the validation described in this section is intended to be compared to the code points listed in Appendix B.1. of RFC 5892, it would be better to refer to IDNA Rules and Derived Property Values <https://www.iana.org/assignments/idna-tables-12.0.0/idna-tables-12.0.0.xhtml> listing the latest IDNA Derived Property Values.