Beware, since the source is a translation of Haskell into C, this is not an entry level source tree and is not straightforward to read/understand despite it's small (LOC) size.

If so, it'll still be interesting to see what they've done with Haskell to make a secure operating system from the L4 model--I assume they are also releasing the Haskell source as well, otherwise there would be no point to it all.