4.4.0-101.124) is not available, but a newer one is (4.4.0-142.168). We redirected you there.
/usr/bin/jets3t-cockpitlite is in jets3t 0.8.1+dfsg-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/bin/../share/jets3t/bin/cockpitlite.sh