How do I reset them?

What do you mean by resetting? In Plasma 5, configuration files are under ~/.config/, names starting with "plasma". Don't delete the plasma-workspace directory if you have scripts in there.

einar wrote:What do you mean by resetting?

I made a few changes to to Plasma's settings (theming) and I'd like to go back to the defaults.

einar wrote:In Plasma 5, configuration files are under ~/.config/, names starting with "plasma".

I'll try deleting those then, thank you.
edit: no dice

Please note that you will probably need to quit Plasma itself before removing the configuration files.
This can be done using the kquitapp utility.

I deleted ~/.kde4 and anything related to KDE in ~/.local/share and ~/.config. That seemed to do the trick. Thanks for the help, I appreciate it.

Sorry to bring this old thread up again...

How about other Plasma5 related applications/frameworks settings?

The thing is that I test out Plasma5 at times by uninstalling KDE4 stuff, testing a bit and going then back to KDE4 if the results are not satisfactory.
Some time ago I did something that started to cause Plasma5 desktop to hang, removing .config/*plasma* does not have any effect on that issue (yes, the desktop itself being really reset to default, but that seems unrelated).