Lighter shadows means less eye adapt / dynamic luminance. The eye adapt adjust screen brightness to keep local area bright. So, if you drive into shadows using default FUEL settings, you can end up with super-bright bloom coming outside the shadow when looking at sunny areas. But, with ligher shadows, there's less difference between shaded and sunny areas, so less eye adapt effect. You still get bloom, but you can see outside the shadow. This is all adjustable in the _setup.h file.
FUEL: RESHADED experimental v3.5
Lighter shadows means less eye adapt / dynamic luminance. The eye adapt adjust screen brightness to keep local area bright. So, if you drive into shadows using default FUEL settings, you can end up with super-bright bloom coming outside the shadow when looking at sunny areas. But, with ligher shadows, there's less difference between shaded and sunny areas, so less eye adapt effect. You still get bloom, but you can see outside the shadow. This is all adjustable in the _setup.h file.