Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8

Hi everyone!

Yesterday I started my journey into Linux (Opensuse Tumbleweed with KDE).
So far everything’s working more or less, except for some issue involving locales, languanges, and some such things, and I can’t progress at all, since I have no clue where to look.

The first issues arose when I was installing R librariers. During the building process, there where error messages about, IIRC, LC_measures, LC_units not being available and C being chosen as a fallback. I know I’m a bit vague, but since the packages compiled I didn’t think much of it and didn’t write it down.

Today, I set up my terminal: Konsole using zsh.

I’m using fzf and have set up the following alias in the zsh config:

alias fzo='xdg-open "$(fzf)"'
eval "$(fzf --zsh)"

fzf is a fuzzy file finder, and the above then allows me to open the file via the defaul app.
This works, but I get the following errors when opening a pdf:

Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
If this causes problems, reconfigure your locale. See the locale(1) manual
for more information.
kf.windowsystem: static int KX11Extras::currentDesktop() may only be used on X11
QAbstractAnimation::pause: Cannot pause a stopped animation

This is the error message for a png:

Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
If this causes problems, reconfigure your locale. See the locale(1) manual
for more information.
kf.windowsystem: static int KX11Extras::currentDesktop() may only be used on X11
QAbstractAnimation::pause: Cannot pause a stopped animation

And here is yet another such message:

Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.     15:40
Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
If this causes problems, reconfigure your locale. See the locale(1) manual
for more information.
kf.i18n.kuit: "Unknown subcue ':whatsthis,' in UI marker in context {@info:whatsthis, %1 the action's text}."
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/hej2k"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-aptus-mos"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-arq"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-bay"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-bmq"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-cap"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-cine"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-cs1"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-dc2"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-drf"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-dxo"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-epson-eip"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-epson-erf"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-fff"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-hasselblad-3fr"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-iiq"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-kodak-dcs"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-kodak-kc2"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-mamiya-mef"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-mfw"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-minolta-mdc"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-mng"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-obm"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-ori"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-ptx"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-pxn"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-qtk"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-r3d"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-raw"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-rdc"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-rwl"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-rwz"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-samsung-srw"
org.kde.kdegraphics.gwenview.lib: Unresolved mime type  "image/x-sti"
org.kde.kdegraphics.gwenview.lib: Unresolved raw mime type  "image/x-samsung-srw"
Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
If this causes problems, reconfigure your locale. See the locale(1) manual
for more information.

Here is another type of warning message, produces by xdg-open .:

Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
If this causes problems, reconfigure your locale. See the locale(1) manual
for more information.
Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
If this causes problems, reconfigure your locale. See the locale(1) manual
for more information.
Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
If this causes problems, reconfigure your locale. See the locale(1) manual
for more information.
Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
If this causes problems, reconfigure your locale. See the locale(1) manual
for more information.
kf.kio.core: An error occurred during write. The worker terminates now.
Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
If this causes problems, reconfigure your locale. See the locale(1) manual
for more information.
kf.kio.core: An error occurred during write. The worker terminates now.
Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
If this causes problems, reconfigure your locale. See the locale(1) manual
for more information.
qt.qpa.wayland: Creating a popup with a parent, QWidgetWindow(0x5603fe07e730, name="Dolphin#1Window") which does not match the current topmost grabbing popup, QWidgetWindow(0x5603feb2d610, name="DolphinContextMenuClassWindow") With some shell surface protocols, this is not allowed. The wayland QPA plugin is currently handling it by setting the parent to the topmost grabbing popup. Note, however, that this may cause positioning errors and popups closing unxpectedly. Please fix the transient parent of the popup.
qt.qpa.wayland: Creating a popup with a parent, QWidgetWindow(0x5603fe07e730, name="Dolphin#1Window") which does not match the current topmost grabbing popup, QWidgetWindow(0x5603feb2d610, name="DolphinContextMenuClassWindow") With some shell surface protocols, this is not allowed. The wayland QPA plugin is currently handling it by setting the parent to the topmost grabbing popup. Note, however, that this may cause positioning errors and popups closing unxpectedly. Please fix the transient parent of the popup.
[29217, Main Thread] WARNING: Locale not supported by C library.
        Using the fallback 'C' locale.: 'glib warning', file /home/abuild/rpmbuild/BUILD/firefox-125.0.2/toolkit/xre/nsSigHandlers.cpp:187

(firefox:29217): Gtk-WARNING **: 16:00:24.612: Locale not supported by C library.
        Using the fallback 'C' locale.

This is the output of locale

locale: Cannot set LC_ALL to default locale: No such file or directory
LANG=en_US.UTF-8
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME=en_AT.UTF-8
LC_COLLATE="en_US.UTF-8"
LC_MONETARY=en_AT.UTF-8
LC_MESSAGES="en_US.UTF-8"
LC_PAPER=de_AT.UTF-8
LC_NAME=de_AT.UTF-8
LC_ADDRESS=de_AT.UTF-8
LC_TELEPHONE=de_AT.UTF-8
LC_MEASUREMENT=en_AT.UTF-8
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=

Additionally, fastfetch tells me

Locale: en_US.UTF-8

A couple of things: I’m using English (US) for everthing text and proper numbers. Everything else is configured to match my local conventions (Austria).
This works as expected, allthough I don’t understand why there are things like en_AT.UTF-8 in the mix (to my understanding there is only de_AT), respectively why sometimes there are quotes, and sometimes there are none. Mind you, this file was created by the installer, I didn’t change anything manually. Furtermore, according to locale -a I have available

[...]
de_AT
de_AT@euro
de_AT.utf8
[...]

Yet, when I use Yast for language things, and want to set primary language to German (de_AT) I get

Language 'de_AT' was not found within the list of supported languages
available at /usr/share/YaST2/data/languages.

I don’t think it matters at all, but for the sake of completness: my keyboard layout is eu

Now, the emberassing part.
I understand there are ways to regenerate locales, respectively reinstall them, but I only found the terminal commands for Ubuntu…
Also, there seem to be an awful lot of places, where locales can be set.
Hence, I’m a loss. Especially since I’m on my second day of Linuxing, I frankly have no clue left where to look.

If there is any additional information I should provide, I’l happily do so.
Thank you so much!

Welcome to the club.

plasma6-workspace is still built without support for dynamic locale generation.

I do not know what en_AT is supposed to be. If you intended to have English time/date - just copy (or link) /usr/lib/locale/en_US.utf8 to /usr/lib/locale/en_AT.utf8. If you really want to have some mix of English and (Austrian-)German - you would need to install glibc-i18ndata, edit locale definition and use localedef to generate it.

About the mixture of English and German stuff…my take away is, that, since it works as I want it to, I just leave it, even if the config doesn’t make a whole lot of sense, correct?

And with respect to the errors it’s the same…as long as it works, there is no problem, and I can’t fix it, since its the responsibiliy of any of the three involved parties?