[tz] Preparing to fork tzdb

[Paul Eggert]

On 9/23/21 7:37 AM, Tom Lane via tz wrote:
> Timekeeping laws are generally set at the country level.

I wouldn't put it that way.

The EU sets timekeeping rules that are binding across member states. 
Although members have some flexibility, so far it's been very unlikely, 
for example, that Sweden would diverge from Germany. (This may of course 
change in the future, in which case we'll of course deal with it.)

Conversely, although the US federal government sets overall rules, it 
devolves DST decisions to states. If the rule were "at least one Zone 
per political unit that has the legal power to set its own rules", we'd 
have dozens more Zones than we do now, Zones that would cause more 
trouble than they'd cure.

Although most countries do set timekeeping laws at the country level, 
counterexamples are so numerous and significant that it's too much to 
say that they're generally set that way.