Meta-Rig 2.53 Beta doc?

Anyone know if there is an explanation of the rigs packed in 2.53 somewhere?

I don"t know if there is official documentation yet but they are there to save you some time. you are supposed to use them as a base then change it and add constraints until you get what you want. not all of them are there yet but it will be really nice once they are. making a human rig can be very time consuming.