/usr/lib/ghc-doc/hoogle/pureMD5.txt is in libghc-puremd5-doc 2.1.2.1-3build3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-puremd5-doc/html/pureMD5.txt