A brief note of explanation (since not everyone will have read the spec!)
  1. CLDR uses inheritance, so child locales inherit from their parents. Eg fr_CA (French as used in Canada) inherits from fr (French as used in France, = fr_FR)
  2. <...>∅∅∅</...> blocks that inheritance for a particular item, meaning that there will be no value for that locale; the reason for doing that is when the item is not generally understood / used in the locale (such as unfamiliar abbreviations). 
  3. For time zones, when there is no value, an alternative is used (eg UTC-7). 
  4. en_001 is the ancestor of most English variants.

On Tue, Mar 10, 2026 at 8:58 AM Robert Bastian via tz <tz@iana.org> wrote:
There's fallback logic which is fairly involved. en.xml contains the data for American English, hence it has short names for American zones. Most English variants fall back to en_001.xml first, which is "world English" with British spelling (en_GB has country specific data for the United Kingdom, so it shouldn't be in the fallback chain for other countries). en_001 and other locales that fall back to en block the fallback to American short zone names (https://github.com/unicode-org/cldr/blob/main/common/main/en_001.xml#L983).

On Tue, 10 Mar 2026 at 11:42, Guy Harris <gharris@sonic.net> wrote:
On Mar 10, 2026, at 3:32 AM, Robert Bastian <robertbastian@unicode.org> wrote:


And in https://github.com/unicode-org/cldr/blob/main/common/main/en.xml#L4491 as well; what does that do for English in other locales?