It's good news that they've changed the default PostgreSQL character set (encoding) from ASCII to UTF8 in Ubuntu 16.04. It'll definitely save a good amount of time of new PostgreSQL users who need UTF8 encoding as default.
No it's not the "default" the default is 'use locale settings'.
So LANG=de_DE.UTF-8 will load a de_DE.UTF-8 Database, while my LANG previously was en_US.UTF-8, i can change LANG to something different and it will create the cluster to the value I've set my LANG to.
newly setup: