<a href="http://www.filext.com">Filext.com</a> has nothing on it, so it's not likely to be a widely used format.

Where did you get it from? It could be a plain text or binary file used by some games-developing file.
Try opening it in Notepad and see if it is readable. If it is, it'll just be a data file to store information for whatever game it came from.