[tz] Error in Scandinavian tz data

[Stephen Colebourne]

On Wed, 28 Jun 2023 at 18:28, Paul Eggert <eggert at cs.ucla.edu> wrote:
> On 2023-06-28 01:17, Stephen Colebourne via tz wrote:
> > I believe that if tzdb provided a fixed offset pre-1970, but one
> > linked to LMT or common practice in that location
>
> For timestamps before 1970 we could approximate LMT along with a time
> zone abbreviation saying that the UT offset is approximate. Something
> equivalent to this, say:
>
>    Zone America/New_York        -5:00   -       c-05    1970 Jan 1 0u
>                         -5:00   US      E%sT
>
>    Zone Asia/Tokyo      9:00    -       c+09    1970 Jan 1 0u
>                         9:00    Japan   J%sT
>
> The idea would be that a time zone abbreviation "c+NN" stands for "circa
> +NN", where the exact offset is unspecified. Software that cares whether
> an offset is approximate could look in the abbreviation for leading "c+"
> and "c-" (along with looking for "-00", which would continue to have its
> current meaning). POSIX allows "c+" and "c-" at the start of time zone
> abbreviations so this would pass POSIX muster.

Or the name could be something consistent across the globe, like
"LMT", such as "SET" (Solar estimated time). It would probably be
easier to have one consistent name (like LMT) than a prefix.

I think before progressing this further it would need other packagers
to chime in and comment on whether they feel it would be acceptable as
the default setting for tzdb pre-1970.

Stephen