KAUTH_INSTALL_HELPER_FILES uses the variables "KDE_INSTALL_DBUSDIR" & "DBUS_SYSTEM_SERVICES_INSTALL_DIR", which are set by the ECM modules KDEInstallDirs usually. KF5AuthMacros does not include the module "KDEInstallDirs" though, so projects trying to use the macro KAUTH_INSTALL_HELPER_FILES but not using ECM or having included the "KDEInstallDirs" module themselves before will see the call failing with "install FILES given no DESTINATION" or similar. I would propose to fix this by adding additional arguments to pass in explicitly the installation paths. While this adds duplication in typical usage in KDE products, it avoids the dependency of KAuth on ECM, which might help adaption outside of KDE spheres.