Would it be possible to add background shapes to individual system tray elements?

[ryu-ketsueki]

Previously, Psifidotos, maintainer of Latte Dock at the time, created a fork of the system tray that allowed to add background shapes to individual elements in the tray. It was called plasma-systray-latte-tweaks.

I noticed that the Panel Colorizer can already identify and define a color for each of the elements in the tray. Would it be possible to also add a background shape to said elements as option to a background to the entire widget?