Source Code
The latest version of the Haskell Report is currently hosted as a Git repository on https://github.com/haskell/haskell-report (and mirrored to https://git.haskell.org/haskell-report.git).
The source code for this effort was originally kept under version control using darcs, a revision control system implemented in Haskell. You can get the original source code via darcs get http://darcs.haskell.org/haskell-prime/
You can browse the source code or download individual files here.