Calendar Server
cis
icsCalendarResource, icsCalendarGroup, icsCalendarUser
The default time zone for this user, group, or resource calendar. Specifically, a valid time zone from the list found in Standard Time Zones. The value is taken from the ics.conf setting calstore.default.timezoneID.
For a user, a time zone can be assigned explicitly through the user preferences attribute (see icsExtendedUserPrefs), which overrides the domain-level default.
icsTimezone: America/Chicago
2.16.840.1.113730.3.1.757