Tend une main fraternelle.

scratchtray.py

#!/usr/bin/env python3
import os
import signal
import gi
gi.require_version('Gtk', '3.0')
gi.require_version('AppIndicator3', '0.1')
from gi.repository import Gtk, AppIndicator3
import threading
from os import path
import time
import i3ipc

class Indicator():
    def __init__(self):
        self.i3 = i3ipc.Connection(auto_reconnect=True)
        self.app = 'show_proc'
        self.testindicator = AppIndicator3.Indicator.new(
            self.app, 'non-starred',
            AppIndicator3.IndicatorCategory.OTHER)
        self.testindicator.set_status(AppIndicator3.IndicatorStatus.ACTIVE)       
        def watcher():
            while True:
                time.sleep(1)
                self.i3_scratch = self.i3.get_tree().scratchpad()
                self.testindicator.set_menu(self.create_menu())
                if len(self.i3_scratch.leaves()) == 0:
                    self.testindicator.set_icon('non-starred')
                else:
                    self.testindicator.set_icon('starred')

        thread = threading.Thread(target=watcher)
        thread.daemon = True
        thread.start()

    def create_menu(self):
        menu = Gtk.Menu()
        for leaf in self.i3_scratch.leaves():
            item = Gtk.MenuItem(leaf.window_title)
            item.connect('activate', self.switch_to, leaf)
            menu.append(item)
        item_quit = Gtk.MenuItem(label='Quit')
        item_quit.connect('activate', self.stop)
        menu.append(item_quit)
        menu.show_all()
        return menu

    def switch_to(self, source, leaf):
        leaf.command('focus')

    def stop(self, source):
        Gtk.main_quit()

Indicator()
signal.signal(signal.SIGINT, signal.SIG_DFL)
Gtk.main()

it doesn't work.