As was already discussed on your previous request, this type of change is out of scope for our project, so we won't be adding it, sorry.
https://mm.icann.org/pipermail/tz/2021-May/030088.html

--
Tim Parenti

On Sat, 11 Sept 2021 at 22:02, Cool Gab19 via tz <tz@iana.org> wrote:

I request Etc/GMT-15 or +15 be included in your database

https://github.com/gabtimezone15/tz/blob/d0970deeac9041a1e8a585782ccec3a1ef748f48/etcetera