/usr/lib/ghc-doc/hoogle/ghc-events.txt is in libghc-ghc-events-doc 0.4.2.0-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-ghc-events-doc/html/ghc-events.txt