That magic actually comes courtesy of [SnabbSwitch](https://github.com/SnabbCo/snabbswitch/wiki), latest project of the inimitable Luke Gorrie. Luke is also publishing SnabbSwitch semi-regularly as a [readable program](http://blog.lukego.com/blog/2012/10/24/readable-programs/).

Basically, you write markdown comments in the code and there is a Makefile that uses awk and sed to grab them out, cat some things together and pass it to an awesome LaTeX stylesheet written by Pete Kazmier. See: https://github.com/redline6561/cl-6502/tree/master/src/doc and the Makefile in the parent directory.