Cldr.Calendar.Julian.day_of_week
You're seeing just the function
day_of_week, go back to Cldr.Calendar.Julian module for more information.
Specs
day_of_week(year(), month(), day(), 1..7 | :default) :: {Calendar.day_of_week(), first_day_of_week :: non_neg_integer(), last_day_of_week :: non_neg_integer()}
Calculates the day of the week from the given year, month, and day.
It is an integer from 1 to 7, where 1 is Monday and 7 is Sunday.