/usr/lib/girepository-1.0/JSCore-3.0.typelib is in gir1.2-javascriptcoregtk-3.0 2.4.0-1ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/girepository-1.0/JavaScriptCore-3.0.typelib
/usr/lib/girepository-1.0/JavaScriptCore-3.0.typelib