Please better explain how Arrays are shared

In the [Array docs](https://docs.godotengine.org/en/3.1/classes/class_array.html#description), all we have right now is this line:

> Arrays are always passed by reference.

For someone who does not know what "passed by reference" means it means nothing.

I only learned through painful trail and error and by wasting a lot of time even that Arrays are somehow shared and PoolXArrays are not. I would have searched what "passed by reference" means sooner, if I somehow knew this expression is connected to my Array changing throughout my running project.
I think the Array documentation should have a clear statement about the fact that it is shared, a statement that is even understood by people who do no know yet what "passed by reference" means, or at the very least some hint that those are connected.