/usr/lib/ghc-doc/hoogle/hxt-unicode.txt is in libghc-hxt-unicode-doc 9.0.2-5.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-hxt-unicode-doc/html/hxt-unicode.txt