Low force boost slider now controls wheel response curve (changes balance of forces). Higher values increase middle forces (low and high forces are also boosted, but not so much).
Useful for cars with low downforce (weaker ffb) like Ginetta G40, F-Trainer, F-Vee. It adds more weight in the wheel while cornering. I recommend LFB value between 40-60 for these cars.
It all depends on personal preferences, so experiment with different values.