/usr/lib/ghc-doc/hoogle/mtlparse.txt is in libghc-mtlparse-doc 0.1.2-5.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-mtlparse-doc/html/mtlparse.txt
/usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-mtlparse-doc/html/mtlparse.txt