KF5 applications on Windows stores there config files directly below C:\Users\admin\AppData\Local\ as shown in the following example: G:\bin>kf5-config.exe --path xdgdata C:\Users\admin\AppData\Local\;G:\share\ where G:\ is the application install root. Mostly applications I know uses a subdirectory below this root directory. On KDE4 times the subdirectory Roaming\.kde4\ has been used e.g. C:\Users\admin\AppData\Roaming\.kde4 Because there are more files into this directory, the result is that is is not possible to identify files belonging to KF5 applications, which may be required to be known for example for cleaning data file on a KF5 application uninstall. Additional informations: Parts of KF5 libraries already uses a subdirectory as shown below: G:\bin>kf5-config.exe --path cache C:\Users\admin\AppData\Local\cache\ I found that ksycoca databases are stored into that directory. They will probably be located into a subdirectory cache of the choosen dir.
This is not likely a KF5 issue; applications based on KF5 are simple Qt5 applications, so they use QStandardPaths. Also, please note that kf5-config is deprecated and part of KDELibs4Support; its replacement is qtpaths, which points again in the Qt direction. Cleaning up the files is not different from cleaning any other Qt application. I would close this as NOTABUG.