/usr/lib/ghc-doc/hoogle/libghc-hpack-doc.txt is in libghc-hpack-doc 0.18.1-1build2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-hpack-doc/html/hpack.txt