Indicate private mode windows in sideberry

[Elementari]

Hello,
I'd find it helpful if private mode windows where somehow marked in the sideberry sidebar. It would help keeping in mind that this is a private mode window that will lose its tabs when FF is closed. I know FF also shows this top right, and on new tabs, but still it would be really helpful. It doesn't really matter how - perhaps use the same violet color that FF uses or sth. like that?