I still use gkrellm, but I would much prefer it lived in the system tray, or if tray was gone on the right of the top panel. However, if having a common standar

I still use gkrellm, but I would much prefer it lived in the system tray, or if tray was gone on the right of the top panel. However, if having a common standard for a system tray is not happening it is even less likely for a common panel interface/API. As for systemd services. I see tray's role not as a background task runner, but as a way to show tiny GUI elements in unobtrusively.