If desire had a file extension, it would be .

"I remember back in the day when file extensions had to be three letters."

If you press F2 and change the file extension to .

The file extension is only there for the benefit of the user.

Despite being an application, they often have a file extension.

Generally when this is done a different file extension is used.

Windows actually looks at the content of the file, not just the file extension.

The file extension of pictures and films was there changed to ".

The main file extension used by this program is .

Anyway, the point is that many of these different file extensions are going to be seen in the future, more even than we see now.