Hello, that file is created by several utilities such as lxappearance, Gnome Settings, or any other GTK program that set GTK options for the 2.x version. What kind of problem is it causing you? The solution here is: Do not remove the file, it's even a hidden file.
Anyways, you can try renaming the file, rebooting, and checking if the file is created again or not. If it isn't created again then leave the file renamed and see if nothing breaks (regarding theming), then delete it after you're sure.