Which network does Coinbase use to transfer USDT?

I'm curious to know which network Coinbase utilizes for the transfer of USDT. As a popular cryptocurrency exchange, Coinbase supports a variety of digital assets and networks, but it's essential to understand the specifics when it comes to transactions, especially for those who rely on USDT for trading and stability. Could you provide some insight into the network Coinbase employs for the seamless transfer of this particular stablecoin? It would be greatly appreciated.