BUG #16532: Contact and "en_NZ.UTF-8"

The following bug has been logged on the website:

Bug reference:      16532
Logged by:          Anrik Drenth
Email address:      drentha@gmail.com
PostgreSQL version: 12.0
Operating system:   Ubuntu
Description:

Hi,

I cant get to (https://www.postgresql.org/list/pgsql-novice/) anymore. It
displays the error:  

Error 503 Backend fetch failed, Backend fetch failed, Guru Meditation:, XID:
71640254, Varnish cache server

The question I wanted to ask, on postgres 12:  
'en_NZ.UTF-8'  seems to be missing for: lc_messages, lc_monetary,
lc_numeric, and lc_time

How do I implement this... or do I?

Thanks

Anrik