For example Slack or Telegram or something else. The program has a single window, I click the “x” and it is closed. GNOME doesn’t have a tray with program icons by default, I didn’t install any extensions besides Vitals to monitor the CPU temperature. I don’t even have a visible Dash. Just vanilla GNOME. In Windows, some programs will go to the background and will still be running when you close the window, usually there’s a setting for that in each program. I wonder whether in GNOME I can do the same or if I should change my mindset and leave everything open at all times. This is more of a habit than necessity.
Not sure if this is standard GNOME behaviour but on Fedora Silverblue under the control centre (where volume, bluetooth etc are) there is a Background Apps section if an app is running in the background.
I forgot about that! Indeed, I just closed Telegram and Slack and they are shown in the menu. Thanks!
Keep in mind that this will only work with apps that support the appropriate xdg-portal (eg flatpaks) other apps might not show up there, despite running in the background.