How to clone Greg Kroah-Hartman's stagingtree repository for the Linux kernel?

I am using git to try and clone Greg Kroah-Hartman’s staging tree repository by using following command.

$ git clone -b staging-next git://

However, I keep getting this error:

Cloning into 'staging'...
fatal: unable to connect to[0:]: errno=Connection refused[1:]: errno=Connection refused[2:]: errno=Connection refused[3: 2620:3:c000:a:0:1991:8:25]: errno=Network is unreachable[4: 2001:4f8:1:10:0:1991:8:25]: errno=Network is unreachable

What is the correct git command line to use?

Git Baby is a git and github fan, let's start git clone.