Other executable filename extensions can be registered with the system as well.
Commonly text files containing this information would have the filename extension '.
The full stop and the three letters which Word has added to your document filenames are called a filename extension.
You should work out what your needs are and compile a list of suitable filename extensions.
By all means, Apple should recommend and support the use of filename extensions for interoperability.
This particular file format uses more than one filename extension.
The filename extensions are successively added at each step of this process.
That's why the filename extension of video files is ".
The filename extension was originally used to easily determine the file's generic type.
Unfortunately for Apple, the matter of filename extensions is not entirely in their hands.