VSCode server, how does the Authorization work?

I came across an interesting MFA type authorization using VSCode Server

https://code.visualstudio.com/blogs/2022/07/07/vscode-server

You install the server on your remote machine then it asks you to visit a URL to GitHub and enter a code generated in your terminal

You do this and then you can see the device in your VSCode.dev remotes section

It's rather nice from a terminal I wonder what's being done here?