FIle variable for steno.el file

[Alan]

Steno files have a first line, thus:   -*-Steno-*-

It is not working for me to put a file variable on the first line, and
since these files are visited and added to at the end of the file,
neither is it possible to put a file variable list at the end of the
file (or so I assume).

How to treat the first line?  Is it a mode?  If so, why doesn't it say
"mode: Steno"?

Thank you.  I hope someone can explain to me how to add a file
variable for a fill-column of 300.

Alan Davis