What Linux distro does China use?

I'm curious, could you elaborate on the Linux distribution used by China? Is there a particular distro that's widely adopted across the country, or does it vary depending on the region or the specific application? I'm particularly interested in understanding if there are any government-backed or endorsed distros, and if so, what factors have contributed to their popularity. Additionally, how do these distros compare to other popular options, both in terms of performance and security?