/usr/lib/x86_64-linux-gnu/libnemo-extension.so is in libnemo-extension-dev 1.8.4-1.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libnemo-extension.so.1.4.0
/usr/lib/x86_64-linux-gnu/libnemo-extension.so.1.4.0