Right, it is not an official standard, but TZDIR appears in tzselect, which comes from GNU libc. https://www.unix.com/man-page/redhat/8/TZSELECT/
date(1) does not set timezone dir: but it uses TZ, and, in man, it refers to tzselect:
> use tzselect to find TZ"
On Mon, Oct 21, 2024 at 6:16 PM Tom Lane <tgl@xxxxxxxxxxxxx> wrote:
Anatolii Smolianinov <zarkonesmall@xxxxxxxxx> writes:
> As I've mentioned, it's not about embedded really, it is more about support
> of standard $TZDIR mechanics in general.
One problem with your argument is that there's no standard mentioning
TZDIR, nor does it appear to affect actually-standard utilities
like date(1).
regards, tom lane
