/usr/lib/ghc-doc/hoogle/gtksourceview2.txt is in libghc-gtksourceview2-doc 0.12.3.1-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-gtksourceview2-doc/html/gtksourceview2.txt