Look at this owl. The “haze” is caused by the camera being placed very close to the grid of the aviary, but the new module “Haze removal” does a wonderful job removing the grid.
Another option is to use “Local Contrast” but the result is not so convincing.
Foliage Removal tool would be good here…
But “Foliage Removal” doesn’t exist in RT or in Darktable for that matter. Does it?
Er… no 
I have also used the haze removal tool to add contrast to a washed out looking image. It was backlit and taken with a vintage lens without any fancy coatings.
So yes, haze removal is useful for many types of images that could use more contrast and/or saturation.
That’s already available, but doesn’t work on conifers unfortunately. It’s called autumn.
Might not have the patience…
