/usr/lib/ghc-doc/hoogle/ltk.txt is in libghc-ltk-doc 0.12.1.0-3build2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-ltk-doc/html/ltk.txt
/usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-ltk-doc/html/ltk.txt