[tz] macOS implements Links with file copies?

[Steve Summit]

Deborah Goldsmith wrote:
>> The OTA time zone update distribution machinery does not currently
>> support the preservation of hard links, so when /usr/share/zoneinfo
>> points at an OTA update, there are no hard links.

Guy Harris replied:
> So how many /var/db/timezone/tz/{version} tzdbs are kept around?
>	$ ls /var/db/timezone/tz
>	2020d.1.0	2020f.1.0	2021a.1.0

What's fascinating to me is that they are there at all.  I'm a
foot-dragging Luddite who rarely accepts any of the upgrades that
vendors push at me -- and yet now that I look, I've got those
same three fresh tz trees sitting there on my Mac, too, one from
as recently as three weeks ago.

Did everybody else know this?  Apologies for making a big deal
out of it if everybody else already knew this.  Evidently OTA
is chugging away there quietly in the background, upgrading
tzdata completely transparently.  (I'm not complaining, I'm just
surprised.)  Anybody know if there's a connection between OTA's
tzdata distribution mechanism, and TZDIST?  I'm guessing not.
(But now I'm wondering if the reason I haven't heard much about
TZDIST lately is that OTA has rendered it obsolete, or something.)