You're seeing just the function year_of_era, go back to Cldr.Calendar.Julian module for more information.


year_of_era(year()) :: {year(), era :: 0..1}

Calculates the year and era from the given year. The ISO calendar has two eras: the current era which starts in year 1 and is defined as era "1". And a second era for those years less than 1 defined as era "0".