The settings, caches and other files needed by KDE applications are stored in several default locations. Since these locations can collide when using multiple installations of KDE software side-by-side, we have added patches to make it possible to adapt those pathes. These changes had been (silently) introduced with KDE 4.8 and have gotten a major rework for the KDE 4.10 based applications.
A sample kde.conf looks like that:
[KDE] KDEHOME=%APPDATA%\\KDE\\kde [XDG] XDG_DATA_HOME=%APPDATA%\\KDE\\kde\\data_home XDG_CONFIG_HOME=%APPDATA%\\KDE\\kde\\config_home