Returns the abbreviation of the day of the week of a date. If no argument is given, then the current local date/time, as returned by date:date-time is used as the default argument. The result is a three-letter English day abbreviation: one of 'Sun', 'Mon', 'Tue', 'Wed', 'Thu' or 'Fri'.
day-abbreviation($date-time as string?) ➔ string
The input date/time
Links to specifications
Notes on the Saxon implementation
The specifications of the EXSLT date-and-time handling functions have little to say about timezones. Saxon generally handles inputs with or without a timezone, and uses the XPath 2.0 concept of implicit timezone to interpret the meaning of dates/times without a timezone. The current date and time used by EXSLT functions is the same as that used by the XPath 2.0 current-dateTime() function.