/usr/lib/x86_64-linux-gnu/libjavascriptcoregtk-3.0.so is in libjavascriptcoregtk-3.0-dev 2.4.10-0ubuntu0.14.04.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libjavascriptcoregtk-3.0.so.0.16.18