RNGを持っているのは誰ですか？カジノまたはソフトウェア開発者？

So far, I thought the software developer was has a RNG built into their software. However, based on several online articles, I understood that each casino has its own RNG. It makes sense. That's why a casino needs an audit, right?

Or do I understand it completely wrong? Does a software developer himself insert a RNG into its games? Or is a casino putting it there?

Thank you for answer...

I believe that game providers have RNG implemented on their servers. Whenever you play in a casino, you actually send requests to the game provider's server and then you receive the reply back to the casino and then the casino displays the result on your screen. But the casinos don't influence the results of your spins, neither the RNG.