/usr/lib/ghc-doc/hoogle/web-routes-th.txt is in libghc-web-routes-th-doc 0.22.1-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-web-routes-th-doc/html/web-routes-th.txt