I'd like to suggest that the top-bar tag be done away with. I propose the following criteria:
- if the "thing" can be used by itself, or customised by itself, it might make sense to refer to it with tag - in which case we tag it with a suitable name, like mate-panel, budgie-panel, xfce4-panel, lxpanel (which are the names of the respective software, afaict), or, alternatively, with panel + name-of-de.
- if the "thing" is an inflexible component of something else, which can't be customised or used on its own, but only via the larger something else, then we should tag it with that something else - gnome-shell, cinnamon...