/usr/share/postgresql/9.5/timezonesets/Australia is in postgresql-9.5 9.5.14-0ubuntu0.16.04.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27  | # Time zone configuration file for set "Australia"
# The abbreviations set up by this file are no longer in widespread use,
# and should be avoided when possible.  Use this file if you need backwards
# compatibility with old applications or data.
# In order to use this file, you need to set the run-time parameter
# timezone_abbreviations to 'Australia'.  See the `Date/Time Support'
#   appendix in the PostgreSQL documentation for more information.
#
# src/timezone/tznames/Australia
# include the default set
@INCLUDE Default
# most timezones are already defined in the default set. With the OVERRIDE
# option, PostgreSQL will use the new definitions instead of throwing an error
# in case of a conflict.
@OVERRIDE
CST     34200    # Central Standard Time (not in IANA database)
EAST    36000    # East Australian Standard Time (not in IANA database)
EST     36000    # Eastern Standard Time (not in IANA database)
SAST    34200    # South Australian Standard Time (not in IANA database)
SAT     34200    # South Australian Standard Time (not in IANA database)
WST     28800    # Western Standard Time (not in IANA database)
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