Perl handling of tzfile (zoneinfo) timezone files

 An instance of this class represents a timezone that was encoded in a file in
 the tzfile(5) format. These can express arbitrary patterns of offsets from
 Universal Time, changing over time. Offsets and change times are limited to a
 resolution of one second.
 .
 DateTime::Timezone::Tzfile implements the DateTime::TimeZone interface, so
 that its instances can be used with DateTime objects.