question: public DateTimeFormatterBuilder appendChronologyText ( TextStyle textStyle ) { Objects . requireNonNull ( textStyle , "textStyle" ) ; appendInternal ( new ChronoPrinterParser ( textStyle ) ) ; return this ; }
target:  Appends the chronology name to the formatter. <p> The calendar system name will be output during a format. If the chronology cannot be obtained then an exception will be thrown.