I guess you are referring to this: # From Arthur David Olson, 2005-12-19 # We generate the files specified below to guard against old files with # obsolete information being left in the time zone binary directory. # We limit the list to names that have appeared in previous versions of # this time zone package. ... # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone EST -5:00 - EST Zone MST -7:00 - MST Zone HST -10:00 - HST Zone EST5EDT -5:00 US E%sT Zone CST6CDT -6:00 US C%sT Zone MST7MDT -7:00 US M%sT Zone PST8PDT -8:00 US P%sT I think that "obsolete information" is the keyword here. These timezones are obsolete but could be used by inexperienced users and therefore they are overwritten by new versions that will presumably be less incorrect. Why "CST" is not defined above when CST6CDT *is* is beyond me, by the way - compare to EST and EST5EDT. Regards, - Jesper Nørgaard Welen -----Original Message----- From: Curtis Doty [mailto:Curtis@GreenKey.net] Sent: Jueves, 18 de Enero de 2007 16:19 To: TZ Subject: variations on GMT-8:00 Hi, this is just historical curiosity. I notice that "Rule CA" is applied to Zone America/Los_Angeles (and therefore US/Pacific and US/Pacific-New). But Zone PST8PDT does not have these same (California?) rules. Is there a political precedence for this? ...