/usr/lib/libsundials_nvecserial.so is in libsundials-serial-dev 2.4.0-5.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libsundials_nvecserial.so.0.0.2
/usr/lib/libsundials_nvecserial.so.0.0.2