"Commenter Burninator discovered that you don't even need the
.desktop ending in the attachment. The Gnome and KDE desktops
actually read the file, and don't base their decision to
special-case the file on the file-name extension! So, the critical
meta data here (make this something that can be executed) is NOT
encoded in the filename, as some have suggested, it is actually
derived by reading the first line of the file contents. So, in that
respect the desktop environments are not quite as hapless as some
had indicated and are not just making the same mistake as Windows
has.
"On the flip-side of that same discovery: You can make your
attachment now even less suspicious looking. Rather than naming it
something like some_text.odt.desktop, you only need to name it
some_text. That has two nice side effects: Firstly, email clients
will now never know what to do with the file (no useful extension)
and are more likely to prompt the user to save the file to disk.
Thus, you don't need to get the user to explicitly do that anymore
by putting proper wording in your email."