/usr/lib/libgtksourceview-2.0.so.0 is in libgtksourceview2.0-0 2.10.5-0ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libgtksourceview-2.0.so.0.0.0
/usr/lib/libgtksourceview-2.0.so.0.0.0