var unicode.Cn

4 uses

	unicode (current package)
		tables.go#L13: 	"Cn": Cn,
		tables.go#L5142: 	Cn     = _Cn // Cn is the set of Unicode characters in category Cn (Other, not assigned).

	regexp/syntax
		parse.go#L1724: 		return unicode.Cn, unicode.Cn, -1 // invert Cn (unassigned)