[Feature] Respect Layer Window Rule (maybe a bug?)

[Pentasis]

Is your feature request related to a problem? Please describe.
It happens in a few programs, but the most prominent and irritrating is the Picture-in-Picture of Firefox. It doesn't work by default (under Wayland) in KDE but one can set the "Layer" in "Window Rules" to either "On-Screen display" or "Overlay". I also tried others (like "popup" etc.)

Describe the solution you'd like
Either respect window layers by default, or add the ability to add it as a rule in the Karousel-settings rules.

Describe alternatives you've considered
I have tried adding a rule like so:

{
    "class": "Firefox",  # (also tried "firefox firefox")
    "caption": "Picture-in-Picture",
    "tile": false
}

but for some reason it won't work.

[heddxh]

I also want it to respect window layer.

But, Firefox PiP works for me with following rule:

{
    "class": "firefox.*",
    "caption": "画中画",  # Chinese for me, I think Picture-in-Picture is correct
    "tile": false
}

Maybe you forget to disable and re-enable it?