Gimp 3/Python How to preset filename

Applications
1

Having this:

procedure.add_file_argument("Your File",
                            _("specify file:"),
                            _("specify file:"),
                            Gimp.FileChooserAction.OPEN,
                            False, None,  # None ok?, Default
                            GObject.ParamFlags.READWRITE)

How can I predefine a filename instead of None?

2 
file=Gio.File.new_for_path('/path/to/file')

or

file=Gio.File.new_build_filenamev(['path','to','file'])
3

Thank you, ofnuts. Works fine.

One additional question:
What’s the variable for the plug-ins dir?
something like gimp_plug_in_directory

4

Gimp.directory() is the root of the user profile.

The doc also mentions a directory_file() function but it doesn’t show in the Python bindings.

5

Thanks again.
That helped.