[tz] [PATCH 2/3] Replace some zones with links when that doesn't lose non-LMT info.

[Paul Eggert]

Zoidsoft wrote:
> so they probably did an interpolation and preferred
> weekends for setting this change

That's pretty much what I inferred from looking
at the Shanks data.  Partly it's because I use
the same process when doing my own research.
See, for example, the latest change to
Pacific/Johnston.

For the proposed changes to America/Anguilla etc.
the most likely explanation is that Shanks et al. lacked 
transition info and guessed, and (worse) guessed
different transition times in different locations
because they made individual guesses and didn't
check their work later.

The tz data have long been maintained trying to fix
stuff like this when I find it.  In several places
I've corrected Shanks data when I think it's bogus, even
if I can't prove it's bogus.  These are noted in the
comments.

> they guard this information as to
> exactly what criteria they used as a secret

That's where we differ from Shanks.  The new Pacific/Johnston
entry has a comment saying that it's guesswork, and
giving the primary source on which the guesswork is
based.  It's another place where Shanks is incorrect
and I'm supplying my own guesswork, but at least
I'm trying to note my assumptions.

Changes like this are a longstanding part of maintenance,
and I'm becoming inclined to think that we shouldn't
discontinue this practice purely from a desire to not
change things.