The Haddock document [1] section 3.3 gives a very simple specification for the module description, but the accompanying examples [2][3] suggest that certain common layout in the module description is picked up and formatted specially. Is there a description of this?

Haddock understands the style of module header that we're using for the hierarchical libraries. The module header is described in this document (see the section Reference Libraries->Coding Style->Module Header): http://www.haskell.org/hierarchical-modules/libraries/libraries.html Cheers, Simon