/usr/lib/ghc-doc/hoogle/async.txt is in libghc-async-doc 2.0.1.4-1build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-async-doc/html/async.txt
/usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-async-doc/html/async.txt