If [code]true[/code], the [Window]'s background can be transparent. This is best used with embedded windows.
[b]Note:[/b] Transparency support is implemented on Linux, macOS and Windows, but availability might vary depending on GPU driver, display manager, and compositor capabilities.
[b]Note:[/b] This property has no effect if either [member ProjectSettings.display/window/per_pixel_transparency/allowed], or the window's [member Viewport.transparent_bg] is set to [code]false[/code].
[b]Note:[/b] This property has no effect if [member ProjectSettings.display/window/per_pixel_transparency/allowed] is set to [code]false[/code].