Standardizing `app-region` for draggable app windows

Hola CSS WG

The WICG has produced a draft for a proposed new feature to extend the web content to the area that would generally be utilized by the title bar, named Window Controls Overlay:
https://wicg.github.io/window-controls-overlay/

The feature consists of an extension to the navigator interface, an new value for the display_override in the manifest and a way to define draggable sections through the CSS property app-region, as seen in the appropriate section in the spec:
https://wicg.github.io/window-controls-overlay/#defining-draggable-sections

I am reaching out to you to ask for feedback and comments, and to evaluate the option (and guidance) of going forward with the standardization process for this property.

Thank you very much!