The earliest FDET actually precedes Wesolowski and Warshel's 1993 paper; that credit should go to Cortona, who proposed the first DFT-in-DFT embedding using KEDFs. As far as I am aware, the first WF-in-DFT embedding utilizing this idea of an embedding potential containing a KEDF potential, as in FDET, was introduced by my group in 1998 in ref. 585, where we carried out, for example, MP4-in-DFT calculations for CO adsorbed on Cu(111). A follow-up, more detailed paper discussing our KEDF-based embedded correlated wave-function (ECW) theory also provides in the introduction important context of earlier embedded WF theories, for those interested in the history of the field. A 2008 review article summarizes the state of embedding (and other) electronic-structure methods for solids at that time. As Wesolowski points out in contribution (4.2.4), the FDET formalism subsequently was generalized by Wesolowski and coworkers to encompass methods beyond DFT, including a correlated wave-function treatment of subsystems.