/usr/lib/x86_64-linux-gnu/libnetsnmpmibs.so.30 is in libsnmp30 5.7.3+dfsg-1ubuntu4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libnetsnmpmibs.so.30.0.3
/usr/lib/x86_64-linux-gnu/libnetsnmpmibs.so.30.0.3