> Don't ask me what happens if the field begins with a letter which has a single form and does not have an explicit upper or lower case. So, on to the spec: ht

> Don't ask me what happens if the field begins with a letter which has a single form and does not have an explicit upper or lower case. So, on to the spec: https://golang.org/ref/spec#unicode_letter https://golang.org/ref/spec#unicode_letter > In The Unicode Standard 8.0, Section 4.5 "General Category" defines a set of character categories. Go treats all characters in any of the Letter categories Lu, Ll, Lt, Lm, or Lo as Unicode letters, and those in the Number category Nd as Unicode digits. Which reads: Lu = Letter, uppercase Ll = Letter, lowercase Lt = Letter, titlecase Lm = Letter, modifier Lo = Letter, other So I suppose (but am not sure) the case you describe falls into Lo.