.FILE File

A FILE is a generic file extension that may be appended to a Windows file that does not have an extension. It is an unknown file type and no associated program will automatically open it.

Since the file has a generic extension, you may try opening a ".file" file by dragging it to applications that you think may open it. If the file is formatted as a text file, you can at least view the contents of the file by opening it in a text editor.