[tz] Transitions after those included in zoneinfo binaries?

[Paul Eggert]

On 12/13/2017 12:41 PM, Zefram wrote:
> the
> extended-POSIX-TZ string at the end of the file specifies the behaviour
> following the last explicit transition.

Yes, and the initial part of this behavior should agree with the info 
associated with the last transition. However, this latter constraint 
wasn't understood until last year, and was addressed only in July 2016:

https://github.com/eggert/tz/commit/081c50f30308b589e7e296f485135d03cf046cb1

and older software doesn't respect it.