/usr/lib/x86_64-linux-gnu/libbpp-popgen.so is in libbpp-popgen-dev 2.4.0-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libbpp-popgen.so.8
/usr/lib/x86_64-linux-gnu/libbpp-popgen.so.8