/usr/lib/ghc-doc/hoogle/libghc-concurrent-output-doc.txt is in libghc-concurrent-output-doc 1.9.2-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-concurrent-output-doc/html/concurrent-output.txt