/usr/lib/ghc-doc/hoogle/libghc-xmonad-extras-doc.txt is in libghc-xmonad-extras-doc 0.13.2-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-xmonad-extras-doc/html/xmonad-extras.txt