GNOME Files (Nautilus) Python extension simple info bar example. Put in ~/.local/share/nautilus-python/extensions/

location-widget-provider.py

from gi.repository import Gtk, Nautilus, GObject

class LocationProviderExample(GObject.GObject, Nautilus.LocationWidgetProvider):
    def __init__(self):
        pass
    
    def get_widget(self, uri, window):
        vb = Gtk.VBox()
        bar = Gtk.InfoBar()
        vb.pack_start(bar, False, False, 0)
        bar.set_message_type(Gtk.MessageType.INFO)
        bar.get_content_area().pack_start(
                Gtk.Label(uri),
                False, False, 0)
        vb.show_all()
        return vb