[racket] Source for Racket Guide

Hello,

I've been reading the Racket Guide and found it really helpful. I'd like 
to be able to read it on my EBook Reader and therefore convert it into 
epub format. How is the guide created: Are the html files in some source 
code repo or only at the website (and I need to download them from there 
and convert into epub)? Or do you generate the html via scribble or some 
other tool (which may allow to generate output as epub)?

Thanks and Regards - Clemens