Manage overlay on icons?

Question

linux

Good day!
Has anyone encountered the task of adding an overlay to folder and file icons in file managers in Linux (Nautilus), Windows and MacOS?
This means the imposition of an additional icon on top of the main system icon. This is done by many applications, plus it is possible to make such settings "by hand". Interested in software implementation on all three operating systems.
Under Windows I found IShellIconOverlayIdentifier.
Under Linux only examples based on calls to gvfs-set-attribute and gvfs-* in general. It would be desirable to do without external calls.
Under Mac, it’s not at all clear where to dig ...
I would be grateful for useful links, examples, and just the right course of searches.

Answer 1

Under poppy, a similar function is called "adding badge" . They say that PyObjc can do this