(or its functional derivative) directly. Early non-decomposable approximations addressed the observation that at the frozen subsystem, the NAKP should fully cancel the attractive nuclear potential, and that GGA KEDFs fail to achieve this . Thus, in Ref. 64 a non-decomposable correction to the NAKP was proposed by one of us to enforce the correct behavior in regions in which the active electron density is negligible compared to the frozen electron density.