/usr/lib/ghc-doc/hoogle/libghc-gtk2hs-buildtools-doc.txt is in libghc-gtk2hs-buildtools-doc 0.13.3.1-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-gtk2hs-buildtools-doc/html/gtk2hs-buildtools.txt