/usr/lib/ghc-doc/hoogle/swish.txt is in libghc-swish-doc 0.9.0.7-1build2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-swish-doc/html/swish.txt
/usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-swish-doc/html/swish.txt