/usr/lib/ghc-doc/hoogle/libghc-chart-cairo-doc.txt is in libghc-chart-cairo-doc 1.8.1-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-chart-cairo-doc/html/Chart-cairo.txt