/usr/lib/ghc-doc/hoogle/libghc-system-filepath-doc.txt is in libghc-system-filepath-doc 0.4.13.4-6.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-system-filepath-doc/html/system-filepath.txt