Open UnitEngine.Script.

I would like to open script “CircleCollider2D”

I want to see how this script handles collision when these evens are raised.

OnCollisionEnter2D

OnCollisionExit2D

OnCollisionStay2D

Is it possible to see the script’s code? If so, how?

Unity is not open source. In fact, a lot of its underlying code is written in C++ and compiled elsewhere, so even if you did get access to it, you’d be looking at executable machine code, not a high-level language.

For that case, though, Unity uses the PhysX system for collisions, so those methods are called based on the behaviour of PhysX.

You might find something over there

https://developer.nvidia.com/sites/default/files/akamai/physx/Index.html

but otherwise, no