NCF – Extended list of Neutral creatures.

Well, firstly, as far as I understand, you need to configure the file explorer so that you can manually change the file extension. To do this, you need to uncheck the box next to "Hide extensions for registered file types" in the "File Explorer Options" section. When saving the modified xdb file, you will be asked where to save it. Save it to your desktop, and then manually drag it to the folder in the archive where the original editable file was located (after changing the format to xdb if it is saved as txt).