Hello! This also affects Postgresql Updates as the timezone is written to the configuration file, so for example Debian testing recently upgraded from postgresql-15 to postgresql-16 and if you attempt to follow the instructions in /usr/share/doc/postgresql-common/README.Debian.gz you end up getting an error message about the configuration being incorrect (it's written in 2 places in the configuration file) if the timezone was set to one of the now removed timezones.
-- steev