Frontend
Aussi appelé: emulator frontend , frontends , host app
A frontend is the host application that loads emulator cores, presents the game-selection UI, handles input bindings, and manages save data. RetroArch is the most popular libretro frontend; EmulatorJS is the dominant browser-based one. The frontend doesn't emulate anything itself — emulation logic lives in the cores it loads. Switching frontends keeps your ROMs, save files, and (often) save states; only the wrapper UI changes.