The source links in the Haskell Hierarchical Libraries pages on the web points to the wrong place. It's almost correct. For example the page:

http://www.haskell.org/ghc/docs/latest/html/libraries/mtl/Control-Monad-State.html has a source link that points to: http://darcs.haskell.org/packages/mtl/Control/Monad/State.raw-hs but the correct link is: http://darcs.haskell.org/packages/mtl/Control/Monad/State.hs