/usr/lib/ghc-doc/hoogle/libghc-generic-deriving-doc.txt is in libghc-generic-deriving-doc 1.9.0-1.
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