/usr/share/zoneinfo/posix/America/Halifax is in tzdata 2016d-0ubuntu0.16.04.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/zoneinfo/posix/America/../../SystemV/AST4ADT
/usr/share/zoneinfo/posix/America/../../SystemV/AST4ADT