It is all code I wrote myself and it is just code and some scriptable objects that make it all work. No art or music assets. When I say sound, I mean a sound manager that listens to events from the events manager and plays the sounds assigned to that event.
They're generic systems that weren't created for any specific project, they're designed to be reusable in any project because almost any game I make is going to need sounds, events, saving and an inventory system.