You’re correct, there isn’t an expression for the gravity. It’s by default 10, but I usually use a variable to store the value and set the gravity with that.
Sometimes the manual lists the exposed js values/functions for behaviors, but if not I try to use console.log with an object and then open up the browser debugger and browse the members, sub-members and so forth.
Basically what you’re after is to
1. Find an instance of an object with physics
2. Access the physics behavior instance.
3. That should have a reference to the box2d world. If the behavior instance doesn’t have it then you may find it in the behavior instance’s type which you should be able to find a reference.
4. Once you get the the box2d world you should be able to find the gravity vector.
Anyways that’s the rough process I use to try to find stuff in js.
I’m not on my computer but if you used the browser execute js action you may be able to access the gravity with something like:
this.runtime.getInstanceByUid(3).behaviors[0].type.world.gravity
The names of everything are probably incorrect so I’d have to check along the way with console.log to see what the correct names are. That and it may be a slightly different path.