localtime — Local time zone configuration file
/etc/localtime -> ../usr/share/zoneinfo/…
The /etc/localtime file
                configures the system-wide time zone of the local
                system that is used by applications for presentation
                to the user. It should be an absolute or relative
                symbolic link pointing to
                /usr/share/zoneinfo/, followed by
                a time zone identifier such as
                Europe/Berlin or
                Etc/UTC.  The resulting link should
                lead to the corresponding binary
                tzfile(5)
                time zone data for the configured time zone.
As the time zone identifier is extracted from
                the symlink target name of
                /etc/localtime this file may not
                be a normal file or hardlink.
The time zone may be overridden for individual programs by using the TZ environment variable. See environ(7).
You may use timedatectl(1) to change the settings of this file from the command line.