[ErroneousBosh]

Okay, what's a "system tray" and what would you use it for?

[Natfan]

a container for information related to your system (datetime, battery, networking, along with custom things that 3rd party apps might put in (automated mouse jiggler, chat client etc)

think i3bar if you need a unix-style equivalency

[ErroneousBosh]

Not something I've ever seen (or noticed, at least) or used.

There's a clock at the top of the screen in Gnome.