Regular RC control, no stabilization. All RC inputs are passed through to the servo outputs set by their SERVOx_FUNCTION.
the MAN_EXPO_ROLL, MAN_EXPO_PITCH, and MAN_EXPO_RUDDER parameters will apply exponential to the stick inputs, if non-zero, in this mode. This is for users with transmitters which do not provide this function and desire to “soften” stick feel around neutral.
This assumes that the RC channel is being used as a servo output function instead of one selected by its RCx_OPTION parameter. The only ways in which the input to a servo output function may be different from inputs in this mode is if a configured failsafe or geofence triggers, and Plane takes control.