13 - pref: CalendarFirstDayOfWeek
18 - as the first day of week in the calendar.
20 - "Enable the following languages on the staff interface:"
24 - pref: opaclanguagesdisplay
29 - patrons to change the language they see on the OPAC.
31 - "Enable the following languages on the OPAC:"
38 - for lists of browsable letters. This should be a space separated list of uppercase letters.