How can I view the inside of built-in functions by Roblox?

Help and Feedback Scripting Support
1

Hello.
I do not know why but today suddenly I wanted to know if there are any ways to know the behind-the-scenes of the functions by Roblox.
for example -

local instance  = {} 
instance.__index = instance
instance:FindFirstChild()
    -- What is really happening here 
end

… and many more

Is this possible or can this be only viewed by Roblox Employees?
I have also heard that objects in Roblox studio have been written in C++ and is that true because at first I was told that everything here is lua?
If it is written in c++ then the creation of classes like instance and the style of everything should be different from how we put a template and put methods inside it.

2

I think all of the Core Scripts and Functions are created with Lua. I know this because the Core Scripts are lua, and built-in functions can be performed within lua scripts. The problem is that this may not be true, as C++ can be used to perform actions within studio, I guess what i’m trying to say is that the behind-the-scenes(backend) of the studio is created using a different programming language, so maybe it is run behind the scenes.