When working with a Scene, on the top-right there is a button [3rd from the right] that you click on to show/hide grid; set the grid size; etc…the first option listed is “show mask”.
This draws and removes a square box around the scene…what is this? do you have to show mask and be careful to place objects inside the mask? what is a mask, what is it used for, and when should you show it or hide it?
So it seems it simply shows you a visual indicator of the size of your game window (which presumably can be smaller than the scene, like with a platformer game).
@anon14980890 thank you very much for your answer and the link you provided. I looked and could not find the info you showed above, but your link and your description helped me a lot.