The Lightning Network is separate from the Bitcoin network – it has its own nodes and software, but it nonetheless communicates with the main chain. To enter or exit the Lightning Network, you need to create special transactions on the blockchain.

That's only part of the lightning network because it can transact in msats but when it's going to on-chain the network rounds it down to the closest satoshi to be broadcasted on-chain

It's the protocol it self that's made to break down the bits one more time.. im no dev bro I have no coding skills.. soo to be honest on this question I can honestly honestly say I'm guessing lmao 🤣 but from what I'm reading it simply breaks it down one more time to msats to move faster 🤷🏾🤷🏾