[tz] TZDB use cases

[Guy Harris]

On Oct 5, 2021, at 12:54 AM, Clive D.W. Feather <clive at davros.org> wrote:

> So do Cyprus, the Kingdom of Denmark, France, the Kingdom of the Netherlands,
> Portugal, and Spain.

In which case, for example, let's hope no sufficiently notable financial institution has a significant office in the Canary Islands or Melilla, so that the city-to-tzdb-ID mapping algorithm doesn't have to cope with Las Palmas de Gran Canaria Time, Santa Cruz de Tenerife Time, or Melilla Time - *maybe* the existence of Africa/Ceuta will make the algorithm work for "Ceuta Time" if it also tries {Continent}/{tzdb-ID-ification of city name}.  (A quick search of sec.gov doesn't find any of those, so *maybe* an "XXX Time" -> country -> tzdb region mapping will work for Spain.)