[tz] Recommendations for stable list of timezone ids

[Steve Summit]

Tobias Lindaaker wrote:
>> On 14 Feb 2018, at 04:43 , Clive D.W. Feather <clive at davros.org> wrote:
>> We discussed this a year ago, but from memory it got bogged down in
>> proposals to make the numbers match alphabetical order of names or
>> something like that.
>
> Do you have an archive link to that discussion. I would be interested in
> what the arguments were for that.

It looks to be messages from February 2017 under the Subject lines:

	Version in zoneinfo files?
	Zone ID in binary (was Re: Version in zoneinfo files?)
	ID string in zic's output files

Representative messages are:

	http://mm.icann.org/pipermail/tz/2017-February/024812.html
	http://mm.icann.org/pipermail/tz/2017-February/024822.html
	http://mm.icann.org/pipermail/tz/2017-February/024838.html
	http://mm.icann.org/pipermail/tz/2017-February/024830.html
	http://mm.icann.org/pipermail/tz/2017-February/024825.html
	http://mm.icann.org/pipermail/tz/2017-February/024861.html

> In my opinion it would make the numbers easier to allocate if we did
> not have to care about preserving a particular order, so I am curious to
> learn what the arguments for alphabetical order were.

I don't see any suggestions (in the threads I cited) to keep them
ordered.  The big question seemed to be where to store them in
the zoneinfo files.  There are 15 unused bytes available in the
current format, but it wasn't clear those were enough.

On that note, I would like to advocate *not* burning all 15 of
those bytes on this (or any) proposal!  Who knows what else we
might need them for.  I'd like to use, say, six of those bytes
for the offset and size of a new table of key/value pairs, which
could include version number, original zone name, and all sorts of
other metadata and commentary.  For zoneinfo readers I'm familiar
with, this might not even require a version number bump, as the
new data would appear to be unnecessary binary garbage at the end,
and (hopefully) ignored.