/usr/lib/ghc-doc/hoogle/generic-deriving.txt is in libghc-generic-deriving-doc 1.4.0-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-generic-deriving-doc/html/generic-deriving.txt