/usr/lib/ghc-doc/hoogle/libghc-relational-schemas-doc.txt is in libghc-relational-schemas-doc 0.1.3.1-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-relational-schemas-doc/html/relational-schemas.txt