Bug 514737

SUMMARY:
Plasma has recently had some nice additions for switching between dark and light themes. It would be really nice to use some of them to switch between dark and darker themes (probably some people would also like to be able to switch between light and less light theme). 

I'm aware that there are complexities to this: most of the tooling deliberately filters light and dark separately, and there's no way to specify a theme as being dark or light, within the theme itself. I thought I'd offer what might hopefully be a simple alternative.

It seems that themes are only selectable as a light or dark theme, if they have a background of a certain shade:
https://invent.kde.org/plasma/plasma-workspace/-/blob/master/kcms/desktoptheme/themesmodel.cpp#L213

So, if the background is darker than grey 192, then it is considered a dark theme. If this number were configurable, it would add a lot of flexibility to the dark/light switching.