"metelko":  0x37,
	"monoton":  0x38,
	"ndyuka":   0x39,
	"nedis":    0x3a,
	"newfound": 0x3b,
	"nicard":   0x3c,
	"njiva":    0x64,
	"nulik":    0x3d,
	"osojs":    0x65,
	"oxendict": 0x3e,
	"pahawh2":  0x3f,
	"pahawh3":  0x40,
	"pahawh4":  0x41,
	"pamaka":   0x42,
	"peano":    0x43,
	"petr1708": 0x44,
	"pinyin":   0x45,
	"polyton":  0x46,
	"provenc":  0x47,

		[maxLen]byte{'e', 'n', '-', 'u', 's', '-', 'p', 'o', 's', 'i', 'x'}: -7, // en_US_POSIX"
	}

	altTagIndex = [...]uint8{0, 17, 31, 45, 61, 74, 86, 102}

	altTags = "xtg-x-cel-gaulishen-GB-oxendicten-x-i-defaultund-x-i-enochiansee-x-i-mingonan-x-zh-minen-US-u-va-posix"
)

func grandfathered(s [maxAltTaglen]byte) (t Tag, ok bool) {
	if v, ok := grandfatheredMap[s]; ok {
		if v < 0 {