func toSymbolV3(ppath string) string {
	var bsl strings.Builder
	changed := false
	for _, c := range ppath {
		if ('A' <= c && c <= 'Z') || ('a' <= c && c <= 'z') || ('0' <= c && c <= '9') {
			bsl.WriteByte(byte(c))
			continue
		}

		if c < 0x80 {
			if u, ok := v3UnderscoreCodes[byte(c)]; ok {
				bsl.WriteByte('_')
				bsl.WriteByte(u)
				changed = true
				continue
			}
		}