Half hour time zones missing

Question

In PHP I am using DateTimeZone::listIdentifiers() to get a list of time zones for user selection. This seems to be working fine, but missing from this list are

Answer 1

For example:

Newfoundland time zone identifier is America/St_Johns

[1] http://php.net/manual/en/timezones.america.php

[2] https://en.wikipedia.org/wiki/List_of_tz_database_time_zones