[tz] Proposed patch - Theory notes for backward file

[Zefram]

Stephen Colebourne wrote:
>I'm simply arguing that the Asia/Calcutta ID should only appear in
>backward, with Asia/Kolkata being used everywhere else.
>That way, excluding the backward file has no effect other than
>removing "no longer desirable" IDs.

Once again, these two statements don't match.  The first argues that
there should not be inactive links in non-backward files; the second that
there should not be active links in the backward file.  They're different,
but related, objectives.  I think you're really seeking both.

-zefram