Currently, this logic exists only in the HtmlTimeFormatter class. We want to apply it to other output formats as well.
However, we want to avoid breaking compatibility for existing users so this should not be done by default.
We will add a new formatter option that controls whether the calendar model is shown or not.
Plain text and wikitext formatters will show the calendar model if needed in parenthesis following the formatted date, as so:
13 March 44 BCE (Gregorian)