there's this in core/kbd.c:
keynames[] = {
{ KEY_UP, "up" },
{ KEY_DOWN, "down" },
{ KEY_LEFT, "left" },
{ KEY_RIGHT, "right" },
{ KEY_SET, "set" },
{ KEY_SHOOT_HALF, "shoot_half" },
{ KEY_SHOOT_FULL, "shoot_full" },
{ KEY_ZOOM_IN, "zoom_in" },
{ KEY_ZOOM_OUT, "zoom_out" },
{ KEY_MENU, "menu" },
{ KEY_DISPLAY, "display" },
{ KEY_PRINT, "print" },
{ KEY_ERASE, "erase" },
{ KEY_ISO, "iso" },
{ KEY_FLASH, "flash" },
{ KEY_MF, "mf" },
{ KEY_MACRO, "macro" },
{ KEY_VIDEO, "video" },
{ KEY_TIMER, "timer" },
{ KEY_EXPO_CORR, "expo_corr" },
{ KEY_MICROPHONE, "fe" },
{ 0xFF, "remote" },
{ 0xFFFF, "no_key" },
}