G.2.1.5 Week number %k[date] special text

%k[date]

Is replaced by either the 2-digit ISO week number or the standard week number with leading zero, or a 4-alphanumeric character text of the current week of year
(see Calendar option --starting-day=argument, Calendar option --iso-week-number=yes|no, and Aspects in Internationalization, for further details), e.g.:

The text ‘Today is %K  of week %k’ will be expanded to
==> ‘Today is Monday of week 24’, in case the actual system date is the 10th June 1996.