Only the file extensions.
Slugline's native format, Fountain, is nothing more than plain text. You can edit it anywhere, on any device, in any app that supports text files. The only difference between Fountain and plain text is the
.txt at the end instead of
Because some older apps don't recognize the
.fountain extension as a plain text file, we also give you the option to save your files with the
There's no difference in the contents of the files, nor in how Slugline treats them.