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Missing formats in region and language gnome


I'm trying to change the format in the debian desktop environment
(gnome), when I go where indicated by (1) no formats are available.
Do I need to install extra packages on Debian 9?

The pkg 'task-n' is installed.

Any help is appriciated.

1)  https://help.gnome.org/users/gnome-help/stable/session-formats.html.en

John Doe