Dear Dmacesic,
I found this in the 4.2 code base for you (PlayerInput.cpp):
**const UInputSettings* DefaultInputSettings = GetDefault<UInputSettings>();**
// Take FOV into account (lower FOV == less sensitivity).
APlayerController const* const PlayerController = GetOuterAPlayerController();
float const FOVScale = (**DefaultInputSettings->bEnableFOVScaling** && PlayerController->PlayerCameraManager) ? (DefaultInputSettings->FOVScale*PlayerController->PlayerCameraManager->GetFOVAngle()) : 1.0f;
NewVal *= FOVScale;
you might want also want to check out InputSettings.h
The code above is the only reference I found in the whole code base!