What's rendered by on shade at z depth 80?

https://arcade.makecode.com/developer/game-loop mentions

  • z index 80 : on shade events are run and applied to the screen.

What are these? What’s a good example of one?

I don’t think there is anything built-in, but you can use the game.onShade() API to run code in this step. That’s how the lighting works in the “dark duck” game; after everything else is drawn to the screen the onShade code is run and it “darkens” the pixels based on the light source.