/usr/lib/graphviz/libgvplugin_xlib.so.6 is in libgvc6 2.38.0-7.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/graphviz/libgvplugin_xlib.so.6.0.0
/usr/lib/graphviz/libgvplugin_xlib.so.6.0.0