There was Latin1 characters included in early MIME drafts. I told late Prof. Jon Postel, the rfc editor at that time, that that is a violation of formatting rules and causes a lot of problems and is against internationalization but he answered that it was inevitable because some examples in the drafts need to include non-ASCII characters. So, I said Jon that MIME rfcs and there drafts can avoid including Latin1 characters because examples in the drafts can (and should, of course) be written with MIME format to represent Latin1 characters by ASCII. . As a result, MIME rfcs (1341, 1342 etc.) are published in pure ASCII. Since then until just recently, all the rfcs are published in pure ASCII, though I don't know how deeply Jon understood various problems caused by non-ASCII characters. And, I can see no reason why rfc8187 must include non-ASCII characters only to make rfcs a lot less internationalized. Masataka Ohta