Nov. 9, 2015
9:36 p.m.
Steve Jones <stevejones@OnTimeZone.com> writes:
I have no idea if there should be entries for such unofficial exceptions, but I assume it should be all or none.
Not all of these have their own entries because many of them are served well enough by the official zone that they match (for example, pockets of Indiana that observed EDT unofficially prior to 2006 are served by America/New_York or America/Louisville). As far as I know, tzdb's policy is to have the "borders" of each zone exclusively follow de facto observance, without any distinction between "officially A, unofficially B" vs the bulk of the "B" zone, unless the situation changed some time between 1970 and now.