This might help with applications that can be integrated by using the browser, but don't have an overlay for Linux, like Discord for example.

Use case: By using Discord Streamkit, we can join a call, generate a URL, access on Steam browser, and pin it, very similar on how it works with OBS. However, unlike OBS, Steam won't let the window background to be transparent.

If this feature could be implemented, we would have a proper Discord overlay for voice chat, as currently we have none official, and the community maintained ones have a hard time on supporting Wayland.

I took a few screenshots to explain the problem.

After pinning the window, you still have the background.

This isn't limited to Discord. It might help with any application that can run on browser. This isn't a feature exclusive to Linux but I posted here because it may be pointless for other platforms, as these usually already have several overlays available.