Regarding the 'module', it is https://userbase.kde.org/System_Settings/Default_Applications And, true, if this kde-krusader.desktop does not work under, for example, Awesome WM, and so a different .desktop file should be registered in mimeapps.list, then this is an issue of the 'KDE system manager module'. As it is part of the 'KDE system manager' it appear natural that it only changes the kde(4)-mimeapps.list anyway.