Generalized Kohn-Sham theory, recently extended to both TDDFT 174 and ensemble DFT, 175 provides a useful viewpoint that rigorously justifies the use of nonmultiplicative potentials. In particular, this means that the use of Fock-exchange potential operators (and variants thereof) in hybrid functionals (both global and range-separated), originally viewed as an ad hoc and theoretically unjustified merger of Kohn-Sham and Hartree-Fock theories, are rigorously derived and justified within generalized Kohn-Sham theory. While, for a given system, there is only one exact Kohn-Sham map, there are infinitely many partiallyinteracting systems to which an exact generalized Kohn-Sham map may be formed. This added flexibility has been found to be useful for spectroscopy -in particular, for choosing generalized-Kohn-Sham maps in which the derivative discontinuity is eliminated; see elaboration in contribution (4.1.5).