/usr/lib/x86_64-linux-gnu/libgmp.so.10 is in libgmp10 2:5.0.2+dfsg-2ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libgmp.so.10.0.2
/usr/lib/x86_64-linux-gnu/libgmp.so.10.0.2