On Mon, Jul 5, 2021 at 9:56 AM PG Doc comments form <nore...@postgresql.org> wrote: > Note how the response has a very weird timezone offset. I guess it is valid,
As for whether it's valid, that's coming from the IANA tz dataset. It has a moment that it believes standard time to have begun at each location, in this case: Z America/Mexico_City -6:36:36 - LMT 1922 Ja 1 0:23:24 https://en.wikipedia.org/wiki/Time_in_Mexico#History seems to agree on the year at least. That "local mean time" offset is computed from the location's longitude, for lack of anything better. The tzinfo "Theory" file has a bunch of disclaimers about pre-1970 data though, including "the tz database's LMT offsets should not be considered meaningful".
