On the “System Settings” section “Region & Language”, changing “Time” into “English (Sweden)” “en_SE.UTF-8” and applying, I end up with this error:
“Not all missing packages managed to resolve! language-pack-en”.
I’m using Neon.
Any clue if I am doing anything wrong?
I just wanted to change the date formatting into something as close as possible as “yyyy-MM-dd”.
I did the same on Opensuse Tumbleweed. You need to generate the locale from a locale file. You can find one for the en_SE locale at GitHub - u296/en_SE: en_SE locale for linux. The exact procedure is different from distro to distro so I can’t really help you. It should be the same between Neon and Ubuntu, so you should find infos online pretty easily.
Try with the Danish version first (en_DK.UTF-8) before downloading from github if it is just the formatting you are after. 
The Danish/English might already be included, but the Swedish/English is unlikely to be. And they are the same when it comes to time formatting IIRC.
Fellow svenne här… Tror det är den du är ute efter.
Maybe my post was not very clear, because what I meant is that I would like to also have the date in a specific formatting.
Today in EN_SE would appear as 2024-03-11
Today in EN_DK would appear as 11/03/2024
But thanks anyway for trying to help!
So would Swedish.
The one you reference to is the English formatting, not the Swedish (if you follow the standard).
But a downloaded locale does not have to follow the standard. xD
Not sure witch formatting you are talking about, but if it is the clock you have on panels, you can finetune that in “configure digital clock” (you can just rightclick the clock on the panel) and change “date format” to Custom and then format it as you like.
f.ex “d MMM, ddd” gives “11 Mar, Mon”
yyyy-MM-dd would give 2024-03-11
The one you are trying to change is the SYSTEM locale.
(well not really, they are actually in a different file, but the system locale for Plasma (simplified))
Yes, I can use that solution for the clock, and that’s actually what I’m using right now.
But I just wanted to have it setted as system wide, so that any compatible application would just behave as I would like from the beginning without any further configuration.
In Micro$oft Windows I can change it easly, as it allows me to freely define how I want the date to be displayed system wide, so I just tried to do the same in Neon and ended up with this problem.
Also, I apologize if I didn’t use the correct terminology… What I know about computers is just what I learned myself surfing the internet, my native language is not english, and I’m a total noob with Linux (just jumped in a week or so ago)!
Anyway thanks again!
I will try to find the procedure online and see if I can do that when I get the chance. To tell the truth I hoped the solution to be something simplier than that. 
Anyway it is also my fault wanting to calibrate even the little details I could go without!
Thanks!
Nothing to apologize for.
Let me try to explain.
You are correct that a locale is a file that defines for example date like you are working with now. It also defines things like how to sort files, how contact info is handled, language etc etc.
The setting in KDE is not the actual system locale, but only the locale in KDE (the desktop userspace). Those settings gets saved in ~/.config/plasma-localerc.
So if you download and change locale in KDE settings, you STILL have the system wide locale file (usually located in /etc/locale.conf for arch based and in /etc/default/locale on debian based) that will take president over the KDE locale for things OUTSIDE the user space, like every system (root) application for example.
So changing the KDE locale has very little to do with the system wide locale.
This is by design in Linux. Userspace should NOT be able to control the system, only root (or sudo users) should be able to.
The fact that windows lets you do system changes like that is not an argument for it being better, it is an argument of how insecure windows can be. xD
Arguably, it COULD be implemented, but as you saw above, the locale files for the system is not even in the same place on different systems.
IMHO it also goes against the mentality of linux where the security is build from the bottom (kernel) and upwards.
You’re welcome, don’t hesitate to ask if you get stuck.
Well, it still shows that Windows is better at exposing system configuration graphically. This is definitely something we could improve on, even though most users who care about this configurations probably know how to use a terminal.
Is that really something a desktop should do?
I understand what you are saying, but I am not sure KDE should start trying to change system settings, that is for the distribution to handle.
On my distribution I absolutely can change the system locale graphically in an application, but not through any KDE implementation.
But if you are saying “KDE is now looking into creating tools for controlling system settngs” (kinda like Calamares for installing) then I am all ears.
I meant “we” more generally as the Linux community, not necessarily KDE.
I can assure you that I never meant that M$ Windows solution was better! Just easier in that contest.
By the way thanks for the paths to the locale files, it is always nice to have as many leads to the solution as possible!
Thanks! I just didn’t had time to try the solution posted above yet. Just neet to have enough contiguous time to both break and fix my installation!
Just be careful.
The link posted to the “swedish” locale above is made for arch, not a debian based system. (it seems, I just glanced at it, I could be wrong)
Might be adaptable but most likely NOT like it is described on that github!
But you can probably figure it out pretty easlily.
Also make sure you use the locale on both your system and Plasma.
Good luck!
