The zone.tab file maps countries to zones. You can then traverse the links to get a mapping back from all the zones to countries.
CLDR keeps such an updated mapping in
http://www.unicode.org/cldr/data/common/supplemental/supplementalData.xml
(Search for zoneFormatting. 001 is the UN M.49 code for "the world", and is given to the Etc zones. Etc/Unknown is a CLDR addition that is used where the zone is invalid or unknown.)
Mark
Well, first of all let me apologize for bringing this up again without being
able to offer any further help :-) This question is the reason I joined the
list but was somewhat less ambitious - can anyone help me get a hold of a
list of countries that belong to each rule/zone definition? Some are simple
i.e. the rule name matches the country, but there are some like C-Eur where
an additional list is required to understand which countries are included in
the time zone.
Thank you very much for your help.