I was trying to apply plasma themes I installed from System Settings to Plasma Login Manager; however, it refuses to apply the theme, giving the classic Breeze Light Theme with blue accent colors. I have tried this with several themes including Sweet KDE, Tokyo Night and Nordic. I am aware that PLM does not support SDDM theming; but, I was expecting that I can at least apply color scheme and icons to make it look decent. Also, Apply Plasma Settings option specifically list Color Scheme and Plasma Theme. Am I doing something wrong, also, I must mention that I am using Fedora Kinoite - an Immutable distro.
Oh, I do not need to even check, according to docs, the global path is /usr/share/plasma/, I am using an atomic system; thus, /usr is read-only. Is there a way to make plasma read from /var or another place or should I make a feature request?
If something is configured systemwide by the system admin or superuser, ideally it would go into /etc. (Really, only distro-provided stuff belongs in /usr.)
To the extent that themes contain code as well as config, you could argue that the code part belong in /opt for a systemwide theme.
However I’ve no idea whether you can actually do this with Plasma themes, or whether /usr and ~/.local are your only choices! Maybe someone else knows, but if it’s not possible (and not currently planned) then I’d say it should be a feature request. If it isn’t provided by the distro, it doesn’t really belong in /usr even on a mutable system.