the %U %s %F options

[Steven Shao <shxu1 sh163 net>]

When you create a launcher in gnome and set a command to it, you will
see the form that a command %s or %U or %F. 

I don't know what they do. For example, if you set a gedit launcher, you
see   gedit %U. Why should gnome append the %U to the command? Very
Strange! Who can tell me the reason. or Where can I find the reason in
detial?

Thank you.

Steven Shao.