Comment by Asooka
2 days ago
You also can't put in Cyrillic or CJK characters. It's a user name, not a human name, you should be fine just using the 26 ASCII letters for it. Basically anything that is a computer-centric string should be only ASCII and nothing else, because supporting all of human writing is a never-ending task.
It's also a dangerous one. For example, are a number of variants of "a" that are different characters in Unicode but are often indistinguishable in most fonts and/or at small font sizes: https://util.unicode.org/UnicodeJsps/confusables.jsp?a=abcde....
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