Avoiding approximate NAKE functionals by potential re- Especially for strongly interacting subsystems, the use of approximations for the NAKE and the NAKP often leads to deteriorated results. Hence, there has been considerable interest in getting highly accurate or even exact reference results for the embedding potentials in such calculations over the past years. These are based on the realization that the functional derivative of the noninteracting kinetic energy functional, evaluated for the electron density ρ(r), can be expressed as δT