/usr/lib/ghc-doc/hoogle/haskelldb.txt is in libghc-haskelldb-doc 2.2.2-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-haskelldb-doc/html/haskelldb.txt