[tz] Issues with pre-1970 information in TZDB

[Paul Eggert]

On 9/23/21 15:33, Steffen Nurpmeso wrote:
>   |
>   |For example, Europe/Berlin is wrong for most of Germany before 1970.
> 
> I do not think so?  MEZ (CET) was introduced in 1893-04-01,

Sure, but Berlin was under Russian control just after World War II and 
the Russian commander of the city decided to run Berlin's clocks on 
Moscow time because that matched the Red Army's clocks. This is why 
Europe/Berlin is known to be wrong for most of Germany, as well as for 
Norway and for Sweden.

Really, nobody should be taking the pre-1970 part of tzdb seriously 
unless they really know what they're doing, which they probably don't. 
That part of tzdb is meant primarily to demonstrate that the 
infrastructure can in *theory* specify pre-1970 civil time, even though 
you generally don't want to be *using* that specification outside of 
artificial Zones like PST8PDT and Etc/UTC.