Ah, there it is... an explanation of how anti-lag works in the Raptor, courtesy of C&D (http://www.caranddriver.com/reviews/2017-ford-f-150-raptor-first-drive-review):
Baja mode also tweaks the engine-management program, shutting down fuel flow but keeping the throttle open when the driver jumps off the accelerator. This keeps air flowing through the engine, which in turn keeps the turbos spinning and cuts lag when the driver gets back on the gas.