What is this?

So I tried that TerrainGenerator.capx..

I have a question about some syntax.

What would this mean?

Event:

     Sprite Compare Y:

                      Y = -16

Just not sure what to make of it..

I kind of hope it would mean Check if there is another block at Y-1.

But not sure

It selects sprites that have the Y of -16.

So based on the Layouts coordinates?