Dear Maintainer,
tl;dr: The locales menu does not offer the "C" and "C.UTF-8" locales.
* What led up to the situation?
I have the following locales installed:
% locale -a
C
C.UTF-8
POSIX
de_DE.utf8
The system default is:
% cat /etc/default/locale
LANG=C.UTF-8
* What exactly did you do (or not do) that was effective (or
ineffective)?
* What was the outcome of this action?
The locale menu on the top right corner of the login screen offers one
choice: de_DE.utf8. (The menu option is called "German - Germany".)
* What outcome did you expect instead?
I expected the locales "C" and "C.UTF-8" to be offered in the drop-down
menu as well.
Cheers,
Daniel