ISO/TS 10303-1776:2014-02 specifies the application module for
Extended date.

The following are within the scope of
ISO/TS 10303-1776:2014-02:

• definition of a year, year and month, year and ordinal date, year and week and day of week;
• items within the scope of application module Date time, ISO/TS 10303-1010.