This is an idea for KDE's Privacy goal: https://community.kde.org/Goals/Privacy_Software Essentially, when "High Security Mode" is turned on in some KCM somewhere, kconfig would write configuration data to encrypted databases rather than plaintext files. Perhaps it could even be a single big database rather than individual app-specific databases, since even that would leak which apps were being used.
*** Bug 310226 has been marked as a duplicate of this bug. ***
Why not “[x] encrypt home partition” ?
For the benefit of people using KDE software on a non-encrypted home partition, I suppose.
In retrospect, people with this use case would indeed probably be better served by simply encrypting the entire home partition.