On 9 Nov 2021, at 21:27, Clive D.W. Feather via tz <tz@iana.org> wrote:

Defining what the legal values of fields are and what they mean (see Irish
winter time for an example). What happens if you provide a value that's out
of range?

This is partly why I tried to compile a list of use cases for direct consumption of the source text files:
https://mm.icann.org/pipermail/tz/2021-October/030950.html

Knowing how and why people are using the files helps define what gets “blessed” as a supported interface.

Cheers,
Gil