I suspect that it is the github integration you are interested in? The post-receive hook generates a post request with json-formatted data about the commit. See http://help.github.com/post-receive-hooks/

When i receive such a request i use the object api http://develop.github.com/p/object.html to get a list of files in the repo, and then fetch *.textile and .png files which are new or have a new hash. I don't use their libraries, i just consume the rest interface directly.

I store the files in mongodb together with some metadata, and for processing i use a nice scala web framework called liftweb. For textile parsing i use http://www.eclipse.org/mylyn/downloads/ And for code formatting i use google-code-prettify

Anything else?