/usr/lib/x86_64-linux-gnu/libOSMesa16.so.6 is in libosmesa6 8.0.2-0ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libOSMesa16.so.6.5.3
/usr/lib/x86_64-linux-gnu/libOSMesa16.so.6.5.3