/usr/lib/ghc-doc/hoogle/libghc-convertible-doc.txt is in libghc-convertible-doc 1.1.1.0-5build2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-convertible-doc/html/convertible.txt