It can have one of four forms:

• standardZoneFormat: the string, “zzz,” which is a kind of null value
• AbbreviationZoneFormat: a single alphabetic string other than “zzz,” in which case that’s the abbreviation
• PairAbbreviationZoneFormat: a pair of strings separated by a slash (‘/’), in which case the first string is the abbreviation for the standard time name and the second string is the abbreviation for the daylight saving time name
• ReplacedZoneFormat: a string containing “%s,” in which case the “%s” will be replaced by the text in the appropriate Rule’s LETTER column