Some Fallout 4 mods brighten the Commonwealth with plants and grass. Others, like Moribund World, make it look bleaker.
The word moribund literally means that something is lacking vitality or vigor. With this mod installed on your console, the Commonwealth is transformed into a much darker environment, similar to the previous versions of Fallout.
The developer created this mod in an attempt to recreate the atmosphere of Fallout 3 and Fallout New Vegas. And for a 69.2 KB file, Moribund World does a pretty darn good job.
As you traverse the new version of the Commonwealth you'll notice a change in the lighting and you'll also see a change in the weather. The video below will show you what to expect from both.