What does this Weld Script accomplish that is in a grouped model.?

I'm kinda new to scripting and was wondering what parts are being affected in this script.

function recurse(parent, funcToUse)

for _, v in pairs(parent:GetChildren()) do

funcToUse(v)
recurse(v, funcToUse)

end

end

local firstPart = script.Parent:GetChildren()[1];

recurse(script.Parent, function(object)
if object:IsA("BasePart") and object~=firstPart then

weld = Instance.new("Weld", object)
weld.C0 = firstPart.CFrame:toObjectSpace(object.CFrame)
weld.C1 = CFrame.new()
weld.Part0 = firstPart
weld.Part1 = object

end
end)

The Script is in a model with parts and other models inside 1 model.

Could someone please tell me what parts are being welded or affected by the script? I don't understand and can't see to find out.