BCP 47 'U' extension for the minimal days in first week
Description
Currently, 'u-fw' extension for the "first day of week" is the only available BCP 47 'u' exension related to week data. However, it is not possible to calculate the week number for a particular year without the information of the minimal days in the first week of that year. For example, to write a test program that validates the week number, it would be great to specify a locale that represents the week data, such as "en-US-u-fw-sun-md-one" in which "md-one" represents there should be at least one day to make it the first week of the year. Otherwise, it has to use some existing locale that happens to have firstDayOfWeek/minimalDaysInFirstWeek to test.
Currently, 'u-fw' extension for the "first day of week" is the only available BCP 47 'u' exension related to week data. However, it is not possible to calculate the week number for a particular year without the information of the minimal days in the first week of that year. For example, to write a test program that validates the week number, it would be great to specify a locale that represents the week data, such as "en-US-u-fw-sun-md-one" in which "md-one" represents there should be at least one day to make it the first week of the year. Otherwise, it has to use some existing locale that happens to have firstDayOfWeek/minimalDaysInFirstWeek to test.