Is retained when VBAT being used?

I understand that with a battery connected to VBAT (Photon), the RTC is retained.
But will in that case also be retained?
And what about other time-related issues (DST etc.)?

The time zone is stored in a global variable that’s not retained, so it is not preserved.

If you need the time zone offset to be remembered when on VBAT you’d need to save it in retained memory and restore it on wake.