Looking for simple explanation - How does x360ce actually work?

Hey all,

I am a newbie to the forums and to x360ce.
It was super easy to setup and works great.
I was very curious as to how x360ce actually works? Not looking for a full technical response just how it knows when you launch a game to apply the controller settings without having to run an App everytime.

I have tried searching but couldn't find the answers I was looking for.

Thanks