https://bugs.kde.org/show_bug.cgi?id=484389
This was my report in “importance: NOR wishlist”.
On GNOME, there are several methods and even on Windows, this is possible. I think this should be implemented.
Ubuntu Program which had this functionality already in 2010:
https://launchpad.net/~tsbarnes/+archive/ubuntu/indicator-keylock
Recent GNOME Shell Extension:
GitHub - kazysmaster/gnome-shell-extension-lockkeys: Numlock and Capslock…
Numlock and Capslock indicator for gnome-shell. Contribute to kazysmaster/gnome-shell-extension-lockkeys development by creating an account on GitHub.
XFCE Panel Plugin:
GitHub - oco2000/xfce4-kbdleds-plugin: This is a keyboard leds plugin for the…
This is a keyboard leds plugin for the Xfce panel. Contribute to oco2000/xfce4-kbdleds-plugin development by creating an account on GitHub.
Windows FOSS Program:
GitHub - jonaskohl/CapsLockIndicator: A small utility that indicates the…
A small utility that indicates the state of the Num lock, Caps lock and Scroll lock key. - jonaskohl/CapsLockIndicator
KDE’s native “Lock Key Status”
A) doesn’t show OSD
B) doesn’t show the state always; there is no “yes or no” functionality
C) at least on my system, I don’t know if it’s a bug but I think it’s not, I can’t see NUM and CAPS on the tray. This weird thing happens where the two icons “merge” when both is enabled at the same time - again not being a useful indication of the current state.