Would it be acceptable to put some text like the following?
Internationalized domain names MUST be represented as A-labels
as described in [RFC5890].
NOTE: For experimental use only, domain names MAY be
represented in UTF-8 as described in [RFC5335].
Please, no. If you're interested in the swamp of non-ASCII
domain names and mail addresses, head over to the EAI WG.
NOTE WELL: This list operates according to