General question about EQ2UI_SkinInfo.xml

[Vanyari]

Sorry if this is too much a noob question but couldn't find an answer on Search.

In nearly every individual mod I download it contains the modified .xml and also EQ2UI_SkinInfo.xml

So when I copy each of these mods over into my subfolder within the UI folder it always asks whether I want to overwrite the EQ2UI_SkinInfo.xml that is already there (from previous mods).

Can someone please explain to me what the EQ2UI_SkinInfo.xml actually is and whether or not I should be having it overwrite, not overwrite or whether it even matters?